sudo-rs

Summary

When Defaults targetpw (or Defaults rootpw) is enabled, the password of the target account (or root account) instead of the invoking user is used for authentication. sudo-rs prior to 0.2.10 incorrectly recorded the invoking user’s UID instead of the authenticated-as user's UID in the authentication timestamp. Any later sudo invocation on the same terminal while the timestamp was still valid would use that timestamp, potentially bypassing new authentication even if the policy would have required it.

Impact

A highly-privileged user (able to run commands as other users, or as root, through sudo) who knows one password of an account they are allowed to run commands as, would be able to run commands as any other account the policy permits them to run commands for, even if they don't know the password for those accounts.

A common instance of this would be that a user can still use their own password to run commands as root (the default behaviour of sudo), effectively negating the intended behaviour of the targetpw or rootpw options.

Example

With this in /etc/sudoers:

Defaults targetpw
user ALL=(ALL:ALL) ALL

First run:

user@machine$ sudo -g root whoami
[sudo: authenticate] Password: <password for user>
user

Then run:

user@machine$ sudo -u root whoami
root

Affected versions

sudo-rs prior to 0.2.5 are not affected, since they do not offer Defaults targetpw or Defaults rootpw.

Credits

This issue was discovered and reported by @Pingasmaster.

Summary

If a user begins entering a password but does not press return for an extended period, a password timeout may occur. When this happens, the keystrokes that were entered are echoed back to the console.

Example

Using sudo-rs:

geiger@cerberus:~$ sudo -s
[sudo: authenticate] Password: sudo-rs: timed out
geiger@cerberus:~$ testtesttest

"testtesttest" was entered at the password prompt but not confirmed by pressing return and then waiting for the timeout.

Impact

This could reveal partial password information, possibly exposing history files when not carefully handled by the user and on screen, usable for Social Engineering or Pass-By attacks.

Versions affected

Passwords timeouts were added in sudo-rs 0.2.7 (with a default set to 5 minutes).

Credits

This issue was discovered and reported by @DevLaTron.

Summary

When Defaults targetpw (or Defaults rootpw) is enabled, the password of the target account (or root account) instead of the invoking user is used for authentication. sudo-rs prior to 0.2.10 incorrectly recorded the invoking user’s UID instead of the authenticated-as user's UID in the authentication timestamp. Any later sudo invocation on the same terminal while the timestamp was still valid would use that timestamp, potentially bypassing new authentication even if the policy would have required it.

Impact

A highly-privileged user (able to run commands as other users, or as root, through sudo) who knows one password of an account they are allowed to run commands as, would be able to run commands as any other account the policy permits them to run commands for, even if they don't know the password for those accounts.

A common instance of this would be that a user can still use their own password to run commands as root (the default behaviour of sudo), effectively negating the intended behaviour of the targetpw or rootpw options.

Example

With this in /etc/sudoers:

Defaults targetpw
user ALL=(ALL:ALL) ALL

First run:

user@machine$ sudo -g root whoami
[sudo: authenticate] Password: <password for user>
user

Then run:

user@machine$ sudo -u root whoami
root

Affected versions

sudo-rs prior to 0.2.5 are not affected, since they do not offer Defaults targetpw or Defaults rootpw.

Credits

This issue was discovered and reported by @Pingasmaster.

Summary

If a user begins entering a password but does not press return for an extended period, a password timeout may occur. When this happens, the keystrokes that were entered are echoed back to the console.

Example

Using sudo-rs:

geiger@cerberus:~$ sudo -s
[sudo: authenticate] Password: sudo-rs: timed out
geiger@cerberus:~$ testtesttest

"testtesttest" was entered at the password prompt but not confirmed by pressing return and then waiting for the timeout.

Impact

This could reveal partial password information, possibly exposing history files when not carefully handled by the user and on screen, usable for Social Engineering or Pass-By attacks.

Versions affected

Passwords timeouts were added in sudo-rs 0.2.7 (with a default set to 5 minutes).

Credits

This issue was discovered and reported by @DevLaTron.

Summary

When Defaults targetpw (or Defaults rootpw) is enabled, the password of the target account (or root account) instead of the invoking user is used for authentication. sudo-rs prior to 0.2.10 incorrectly recorded the invoking user’s UID instead of the authenticated-as user's UID in the authentication timestamp. Any later sudo invocation on the same terminal while the timestamp was still valid would use that timestamp, potentially bypassing new authentication even if the policy would have required it.

Impact

A highly-privileged user (able to run commands as other users, or as root, through sudo) who knows one password of an account they are allowed to run commands as, would be able to run commands as any other account the policy permits them to run commands for, even if they don't know the password for those accounts.

A common instance of this would be that a user can still use their own password to run commands as root (the default behaviour of sudo), effectively negating the intended behaviour of the targetpw or rootpw options.

Example

With this in /etc/sudoers:

Defaults targetpw
user ALL=(ALL:ALL) ALL

First run:

user@machine$ sudo -g root whoami
[sudo: authenticate] Password: <password for user>
user

Then run:

user@machine$ sudo -u root whoami
root

Affected versions

sudo-rs prior to 0.2.5 are not affected, since they do not offer Defaults targetpw or Defaults rootpw.

Credits

This issue was discovered and reported by @Pingasmaster.

Summary

If a user begins entering a password but does not press return for an extended period, a password timeout may occur. When this happens, the keystrokes that were entered are echoed back to the console.

Example

Using sudo-rs:

geiger@cerberus:~$ sudo -s
[sudo: authenticate] Password: sudo-rs: timed out
geiger@cerberus:~$ testtesttest

"testtesttest" was entered at the password prompt but not confirmed by pressing return and then waiting for the timeout.

Impact

This could reveal partial password information, possibly exposing history files when not carefully handled by the user and on screen, usable for Social Engineering or Pass-By attacks.

Versions affected

Passwords timeouts were added in sudo-rs 0.2.7 (with a default set to 5 minutes).

Credits

This issue was discovered and reported by @DevLaTron.

Summary

When Defaults targetpw (or Defaults rootpw) is enabled, the password of the target account (or root account) instead of the invoking user is used for authentication. sudo-rs prior to 0.2.10 incorrectly recorded the invoking user’s UID instead of the authenticated-as user's UID in the authentication timestamp. Any later sudo invocation on the same terminal while the timestamp was still valid would use that timestamp, potentially bypassing new authentication even if the policy would have required it.

Impact

A highly-privileged user (able to run commands as other users, or as root, through sudo) who knows one password of an account they are allowed to run commands as, would be able to run commands as any other account the policy permits them to run commands for, even if they don't know the password for those accounts.

A common instance of this would be that a user can still use their own password to run commands as root (the default behaviour of sudo), effectively negating the intended behaviour of the targetpw or rootpw options.

Example

With this in /etc/sudoers:

Defaults targetpw
user ALL=(ALL:ALL) ALL

First run:

user@machine$ sudo -g root whoami
[sudo: authenticate] Password: <password for user>
user

Then run:

user@machine$ sudo -u root whoami
root

Affected versions

sudo-rs prior to 0.2.5 are not affected, since they do not offer Defaults targetpw or Defaults rootpw.

Credits

This issue was discovered and reported by @Pingasmaster.

Summary

When Defaults targetpw (or Defaults rootpw) is enabled, the password of the target account (or root account) instead of the invoking user is used for authentication. sudo-rs prior to 0.2.10 incorrectly recorded the invoking user’s UID instead of the authenticated-as user's UID in the authentication timestamp. Any later sudo invocation on the same terminal while the timestamp was still valid would use that timestamp, potentially bypassing new authentication even if the policy would have required it.

Impact

A highly-privileged user (able to run commands as other users, or as root, through sudo) who knows one password of an account they are allowed to run commands as, would be able to run commands as any other account the policy permits them to run commands for, even if they don't know the password for those accounts.

A common instance of this would be that a user can still use their own password to run commands as root (the default behaviour of sudo), effectively negating the intended behaviour of the targetpw or rootpw options.

Example

With this in /etc/sudoers:

Defaults targetpw
user ALL=(ALL:ALL) ALL

First run:

user@machine$ sudo -g root whoami
[sudo: authenticate] Password: <password for user>
user

Then run:

user@machine$ sudo -u root whoami
root

Affected versions

sudo-rs prior to 0.2.5 are not affected, since they do not offer Defaults targetpw or Defaults rootpw.

Credits

This issue was discovered and reported by @Pingasmaster.

Summary

Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the -U flag. This doesn't happen with the original sudo.

PoC

The initial test has been done in a container running Ubuntu 24.04 and installing oxidizr, running sudo-rs 0.2.2.

A user (bob) has been added with only ps command executable through sudo:

root    ALL=(ALL:ALL) ALL
bob     ALL=(ALL:ALL) /usr/bin/ps

The user is not able to read the /etc/sudoers file and running sudo -l -Uroot with original sudo (version 1.9.15p5) causes the following error:

Sorry, user bob is not allowed to execute 'list' as root on 43d4aed3cdbd.

The same command with sudo-rs is run without denying the execution:

User root may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) ALL

The same happens for other non-root users:

bob@43d4aed3cdbd:~$ sudo -l -Ufoo
User foo may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) /usr/bin/whoami

The behavior has been also been observed for version 0.2.5.

Impact

Users with limited sudo privileges can enumerate the sudoers file, revealing sensitive information about other users' permissions. Attackers can collect information that can be used to more targeted attacks.

Systems where users either do not have sudo privileges or have the ability to run all commands as root through sudo (the default configuration on most systems) are not affected by this advisory.

Credits

This issue was identified by Sonia Zorba.

Summary

Users with no (or very limited) sudo privileges can determine whether files exists in folders that they otherwise cannot access using sudo --list <pathname>.

PoC

As root:

# mkdir /tmp/foo
# chmod a-rwx /tmp/foo
# touch /tmp/foo/secret_file

As a user without any (or limited) sudo rights:

$ sudo --list /tmp/foo/nonexistent_file
sudo-rs: '/tmp/foo/nonexistent_file': command not found
$ $ sudo --list /tmp/foo/secret_file
sudo-rs: Sorry, user eve may not run sudo on host.

I.e. the user can distinguish whether files exist.

Related

Original sudo (vulnerable version tested by us: 1.9.15p5) exhibited similar behaviour for files with the executable bit set.

Impact

Users with local access to a machine can discover the existence/non-existence of certain files, revealing potentially sensitive information in the file names. This information can also be used in conjunction with other attacks.

Credits

This issue was identified by sudo-rs developer Marc Schoolderman

Summary

Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the -U flag. This doesn't happen with the original sudo.

PoC

The initial test has been done in a container running Ubuntu 24.04 and installing oxidizr, running sudo-rs 0.2.2.

A user (bob) has been added with only ps command executable through sudo:

root    ALL=(ALL:ALL) ALL
bob     ALL=(ALL:ALL) /usr/bin/ps

The user is not able to read the /etc/sudoers file and running sudo -l -Uroot with original sudo (version 1.9.15p5) causes the following error:

Sorry, user bob is not allowed to execute 'list' as root on 43d4aed3cdbd.

The same command with sudo-rs is run without denying the execution:

User root may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) ALL

The same happens for other non-root users:

bob@43d4aed3cdbd:~$ sudo -l -Ufoo
User foo may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) /usr/bin/whoami

The behavior has been also been observed for version 0.2.5.

Impact

Users with limited sudo privileges can enumerate the sudoers file, revealing sensitive information about other users' permissions. Attackers can collect information that can be used to more targeted attacks.

Systems where users either do not have sudo privileges or have the ability to run all commands as root through sudo (the default configuration on most systems) are not affected by this advisory.

Credits

This issue was identified by Sonia Zorba.

Summary

Users with no (or very limited) sudo privileges can determine whether files exists in folders that they otherwise cannot access using sudo --list <pathname>.

PoC

As root:

# mkdir /tmp/foo
# chmod a-rwx /tmp/foo
# touch /tmp/foo/secret_file

As a user without any (or limited) sudo rights:

$ sudo --list /tmp/foo/nonexistent_file
sudo-rs: '/tmp/foo/nonexistent_file': command not found
$ $ sudo --list /tmp/foo/secret_file
sudo-rs: Sorry, user eve may not run sudo on host.

I.e. the user can distinguish whether files exist.

Related

Original sudo (vulnerable version tested by us: 1.9.15p5) exhibited similar behaviour for files with the executable bit set.

Impact

Users with local access to a machine can discover the existence/non-existence of certain files, revealing potentially sensitive information in the file names. This information can also be used in conjunction with other attacks.

Credits

This issue was identified by sudo-rs developer Marc Schoolderman

Summary

Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the -U flag. This doesn't happen with the original sudo.

PoC

The initial test has been done in a container running Ubuntu 24.04 and installing oxidizr, running sudo-rs 0.2.2.

A user (bob) has been added with only ps command executable through sudo:

root    ALL=(ALL:ALL) ALL
bob     ALL=(ALL:ALL) /usr/bin/ps

The user is not able to read the /etc/sudoers file and running sudo -l -Uroot with original sudo (version 1.9.15p5) causes the following error:

Sorry, user bob is not allowed to execute 'list' as root on 43d4aed3cdbd.

The same command with sudo-rs is run without denying the execution:

User root may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) ALL

The same happens for other non-root users:

bob@43d4aed3cdbd:~$ sudo -l -Ufoo
User foo may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) /usr/bin/whoami

The behavior has been also been observed for version 0.2.5.

Impact

Users with limited sudo privileges can enumerate the sudoers file, revealing sensitive information about other users' permissions. Attackers can collect information that can be used to more targeted attacks.

Systems where users either do not have sudo privileges or have the ability to run all commands as root through sudo (the default configuration on most systems) are not affected by this advisory.

Credits

This issue was identified by Sonia Zorba.

Summary

Users with no (or very limited) sudo privileges can determine whether files exists in folders that they otherwise cannot access using sudo --list <pathname>.

PoC

As root:

# mkdir /tmp/foo
# chmod a-rwx /tmp/foo
# touch /tmp/foo/secret_file

As a user without any (or limited) sudo rights:

$ sudo --list /tmp/foo/nonexistent_file
sudo-rs: '/tmp/foo/nonexistent_file': command not found
$ $ sudo --list /tmp/foo/secret_file
sudo-rs: Sorry, user eve may not run sudo on host.

I.e. the user can distinguish whether files exist.

Related

Original sudo (vulnerable version tested by us: 1.9.15p5) exhibited similar behaviour for files with the executable bit set.

Impact

Users with local access to a machine can discover the existence/non-existence of certain files, revealing potentially sensitive information in the file names. This information can also be used in conjunction with other attacks.

Credits

This issue was identified by sudo-rs developer Marc Schoolderman

Summary

Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the -U flag. This doesn't happen with the original sudo.

PoC

The initial test has been done in a container running Ubuntu 24.04 and installing oxidizr, running sudo-rs 0.2.2.

A user (bob) has been added with only ps command executable through sudo:

root    ALL=(ALL:ALL) ALL
bob     ALL=(ALL:ALL) /usr/bin/ps

The user is not able to read the /etc/sudoers file and running sudo -l -Uroot with original sudo (version 1.9.15p5) causes the following error:

Sorry, user bob is not allowed to execute 'list' as root on 43d4aed3cdbd.

The same command with sudo-rs is run without denying the execution:

User root may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) ALL

The same happens for other non-root users:

bob@43d4aed3cdbd:~$ sudo -l -Ufoo
User foo may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) /usr/bin/whoami

The behavior has been also been observed for version 0.2.5.

Impact

Users with limited sudo privileges can enumerate the sudoers file, revealing sensitive information about other users' permissions. Attackers can collect information that can be used to more targeted attacks.

Systems where users either do not have sudo privileges or have the ability to run all commands as root through sudo (the default configuration on most systems) are not affected by this advisory.

Credits

This issue was identified by Sonia Zorba.

Summary

Users with no (or very limited) sudo privileges can determine whether files exists in folders that they otherwise cannot access using sudo --list <pathname>.

PoC

As root:

# mkdir /tmp/foo
# chmod a-rwx /tmp/foo
# touch /tmp/foo/secret_file

As a user without any (or limited) sudo rights:

$ sudo --list /tmp/foo/nonexistent_file
sudo-rs: '/tmp/foo/nonexistent_file': command not found
$ $ sudo --list /tmp/foo/secret_file
sudo-rs: Sorry, user eve may not run sudo on host.

I.e. the user can distinguish whether files exist.

Related

Original sudo (vulnerable version tested by us: 1.9.15p5) exhibited similar behaviour for files with the executable bit set.

Impact

Users with local access to a machine can discover the existence/non-existence of certain files, revealing potentially sensitive information in the file names. This information can also be used in conjunction with other attacks.

Credits

This issue was identified by sudo-rs developer Marc Schoolderman

Summary

Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the -U flag. This doesn't happen with the original sudo.

PoC

The initial test has been done in a container running Ubuntu 24.04 and installing oxidizr, running sudo-rs 0.2.2.

A user (bob) has been added with only ps command executable through sudo:

root    ALL=(ALL:ALL) ALL
bob     ALL=(ALL:ALL) /usr/bin/ps

The user is not able to read the /etc/sudoers file and running sudo -l -Uroot with original sudo (version 1.9.15p5) causes the following error:

Sorry, user bob is not allowed to execute 'list' as root on 43d4aed3cdbd.

The same command with sudo-rs is run without denying the execution:

User root may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) ALL

The same happens for other non-root users:

bob@43d4aed3cdbd:~$ sudo -l -Ufoo
User foo may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) /usr/bin/whoami

The behavior has been also been observed for version 0.2.5.

Impact

Users with limited sudo privileges can enumerate the sudoers file, revealing sensitive information about other users' permissions. Attackers can collect information that can be used to more targeted attacks.

Systems where users either do not have sudo privileges or have the ability to run all commands as root through sudo (the default configuration on most systems) are not affected by this advisory.

Credits

This issue was identified by Sonia Zorba.

Summary

Users with no (or very limited) sudo privileges can determine whether files exists in folders that they otherwise cannot access using sudo --list <pathname>.

PoC

As root:

# mkdir /tmp/foo
# chmod a-rwx /tmp/foo
# touch /tmp/foo/secret_file

As a user without any (or limited) sudo rights:

$ sudo --list /tmp/foo/nonexistent_file
sudo-rs: '/tmp/foo/nonexistent_file': command not found
$ $ sudo --list /tmp/foo/secret_file
sudo-rs: Sorry, user eve may not run sudo on host.

I.e. the user can distinguish whether files exist.

Related

Original sudo (vulnerable version tested by us: 1.9.15p5) exhibited similar behaviour for files with the executable bit set.

Impact

Users with local access to a machine can discover the existence/non-existence of certain files, revealing potentially sensitive information in the file names. This information can also be used in conjunction with other attacks.

Credits

This issue was identified by sudo-rs developer Marc Schoolderman

Summary

Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the -U flag. This doesn't happen with the original sudo.

PoC

The initial test has been done in a container running Ubuntu 24.04 and installing oxidizr, running sudo-rs 0.2.2.

A user (bob) has been added with only ps command executable through sudo:

root    ALL=(ALL:ALL) ALL
bob     ALL=(ALL:ALL) /usr/bin/ps

The user is not able to read the /etc/sudoers file and running sudo -l -Uroot with original sudo (version 1.9.15p5) causes the following error:

Sorry, user bob is not allowed to execute 'list' as root on 43d4aed3cdbd.

The same command with sudo-rs is run without denying the execution:

User root may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) ALL

The same happens for other non-root users:

bob@43d4aed3cdbd:~$ sudo -l -Ufoo
User foo may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) /usr/bin/whoami

The behavior has been also been observed for version 0.2.5.

Impact

Users with limited sudo privileges can enumerate the sudoers file, revealing sensitive information about other users' permissions. Attackers can collect information that can be used to more targeted attacks.

Systems where users either do not have sudo privileges or have the ability to run all commands as root through sudo (the default configuration on most systems) are not affected by this advisory.

Credits

This issue was identified by Sonia Zorba.

Summary

Users with no (or very limited) sudo privileges can determine whether files exists in folders that they otherwise cannot access using sudo --list <pathname>.

PoC

As root:

# mkdir /tmp/foo
# chmod a-rwx /tmp/foo
# touch /tmp/foo/secret_file

As a user without any (or limited) sudo rights:

$ sudo --list /tmp/foo/nonexistent_file
sudo-rs: '/tmp/foo/nonexistent_file': command not found
$ $ sudo --list /tmp/foo/secret_file
sudo-rs: Sorry, user eve may not run sudo on host.

I.e. the user can distinguish whether files exist.

Related

Original sudo (vulnerable version tested by us: 1.9.15p5) exhibited similar behaviour for files with the executable bit set.

Impact

Users with local access to a machine can discover the existence/non-existence of certain files, revealing potentially sensitive information in the file names. This information can also be used in conjunction with other attacks.

Credits

This issue was identified by sudo-rs developer Marc Schoolderman

Impact

An issue was discovered where usernames containing the . and / characters could result in the corruption of specific files on the filesystem. As usernames are generally not limited by the characters they can contain, a username appearing to be a relative path can be constructed. For example we could add a user to the system containing the username ../../../../bin/cp. When logged in as a user with that name, that user could run sudo -K to clear their session record file. The session code then constructs the path to the session file by concatenating the username to the session file storage directory, resulting in a resolved path of /bin/cp. The code then clears that file, resulting in the cp binary effectively being removed from the system.

An attacker needs to be able to login as a user with a constructed username. Given that such a username is unlikely to exist on an existing system, they will also need to be able to create the users with the constructed usernames.

Patches

The bug is fixed in version 0.2.1 of sudo-rs. Sudo-rs now uses the uid for the user instead of their username for determining the filename. Note that an upgrade to this version will result in existing session files being ignored and users will be forced to re-authenticate. It also fully eliminates any possibility of path traversal, given that uids are always integer values.

The issue was corrected in commit bfdbda22968e3de43fa8246cab1681cfd5d5493d.

Summary

Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the -U flag. This doesn't happen with the original sudo.

PoC

The initial test has been done in a container running Ubuntu 24.04 and installing oxidizr, running sudo-rs 0.2.2.

A user (bob) has been added with only ps command executable through sudo:

root    ALL=(ALL:ALL) ALL
bob     ALL=(ALL:ALL) /usr/bin/ps

The user is not able to read the /etc/sudoers file and running sudo -l -Uroot with original sudo (version 1.9.15p5) causes the following error:

Sorry, user bob is not allowed to execute 'list' as root on 43d4aed3cdbd.

The same command with sudo-rs is run without denying the execution:

User root may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) ALL

The same happens for other non-root users:

bob@43d4aed3cdbd:~$ sudo -l -Ufoo
User foo may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) /usr/bin/whoami

The behavior has been also been observed for version 0.2.5.

Impact

Users with limited sudo privileges can enumerate the sudoers file, revealing sensitive information about other users' permissions. Attackers can collect information that can be used to more targeted attacks.

Systems where users either do not have sudo privileges or have the ability to run all commands as root through sudo (the default configuration on most systems) are not affected by this advisory.

Credits

This issue was identified by Sonia Zorba.

Summary

Users with no (or very limited) sudo privileges can determine whether files exists in folders that they otherwise cannot access using sudo --list <pathname>.

PoC

As root:

# mkdir /tmp/foo
# chmod a-rwx /tmp/foo
# touch /tmp/foo/secret_file

As a user without any (or limited) sudo rights:

$ sudo --list /tmp/foo/nonexistent_file
sudo-rs: '/tmp/foo/nonexistent_file': command not found
$ $ sudo --list /tmp/foo/secret_file
sudo-rs: Sorry, user eve may not run sudo on host.

I.e. the user can distinguish whether files exist.

Related

Original sudo (vulnerable version tested by us: 1.9.15p5) exhibited similar behaviour for files with the executable bit set.

Impact

Users with local access to a machine can discover the existence/non-existence of certain files, revealing potentially sensitive information in the file names. This information can also be used in conjunction with other attacks.

Credits

This issue was identified by sudo-rs developer Marc Schoolderman

Impact

An issue was discovered where usernames containing the . and / characters could result in the corruption of specific files on the filesystem. As usernames are generally not limited by the characters they can contain, a username appearing to be a relative path can be constructed. For example we could add a user to the system containing the username ../../../../bin/cp. When logged in as a user with that name, that user could run sudo -K to clear their session record file. The session code then constructs the path to the session file by concatenating the username to the session file storage directory, resulting in a resolved path of /bin/cp. The code then clears that file, resulting in the cp binary effectively being removed from the system.

An attacker needs to be able to login as a user with a constructed username. Given that such a username is unlikely to exist on an existing system, they will also need to be able to create the users with the constructed usernames.

Patches

The bug is fixed in version 0.2.1 of sudo-rs. Sudo-rs now uses the uid for the user instead of their username for determining the filename. Note that an upgrade to this version will result in existing session files being ignored and users will be forced to re-authenticate. It also fully eliminates any possibility of path traversal, given that uids are always integer values.

The issue was corrected in commit bfdbda22968e3de43fa8246cab1681cfd5d5493d.

Summary

Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the -U flag. This doesn't happen with the original sudo.

PoC

The initial test has been done in a container running Ubuntu 24.04 and installing oxidizr, running sudo-rs 0.2.2.

A user (bob) has been added with only ps command executable through sudo:

root    ALL=(ALL:ALL) ALL
bob     ALL=(ALL:ALL) /usr/bin/ps

The user is not able to read the /etc/sudoers file and running sudo -l -Uroot with original sudo (version 1.9.15p5) causes the following error:

Sorry, user bob is not allowed to execute 'list' as root on 43d4aed3cdbd.

The same command with sudo-rs is run without denying the execution:

User root may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) ALL

The same happens for other non-root users:

bob@43d4aed3cdbd:~$ sudo -l -Ufoo
User foo may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) /usr/bin/whoami

The behavior has been also been observed for version 0.2.5.

Impact

Users with limited sudo privileges can enumerate the sudoers file, revealing sensitive information about other users' permissions. Attackers can collect information that can be used to more targeted attacks.

Systems where users either do not have sudo privileges or have the ability to run all commands as root through sudo (the default configuration on most systems) are not affected by this advisory.

Credits

This issue was identified by Sonia Zorba.

Summary

Users with no (or very limited) sudo privileges can determine whether files exists in folders that they otherwise cannot access using sudo --list <pathname>.

PoC

As root:

# mkdir /tmp/foo
# chmod a-rwx /tmp/foo
# touch /tmp/foo/secret_file

As a user without any (or limited) sudo rights:

$ sudo --list /tmp/foo/nonexistent_file
sudo-rs: '/tmp/foo/nonexistent_file': command not found
$ $ sudo --list /tmp/foo/secret_file
sudo-rs: Sorry, user eve may not run sudo on host.

I.e. the user can distinguish whether files exist.

Related

Original sudo (vulnerable version tested by us: 1.9.15p5) exhibited similar behaviour for files with the executable bit set.

Impact

Users with local access to a machine can discover the existence/non-existence of certain files, revealing potentially sensitive information in the file names. This information can also be used in conjunction with other attacks.

Credits

This issue was identified by sudo-rs developer Marc Schoolderman

Impact

An issue was discovered where usernames containing the . and / characters could result in the corruption of specific files on the filesystem. As usernames are generally not limited by the characters they can contain, a username appearing to be a relative path can be constructed. For example we could add a user to the system containing the username ../../../../bin/cp. When logged in as a user with that name, that user could run sudo -K to clear their session record file. The session code then constructs the path to the session file by concatenating the username to the session file storage directory, resulting in a resolved path of /bin/cp. The code then clears that file, resulting in the cp binary effectively being removed from the system.

An attacker needs to be able to login as a user with a constructed username. Given that such a username is unlikely to exist on an existing system, they will also need to be able to create the users with the constructed usernames.

Patches

The bug is fixed in version 0.2.1 of sudo-rs. Sudo-rs now uses the uid for the user instead of their username for determining the filename. Note that an upgrade to this version will result in existing session files being ignored and users will be forced to re-authenticate. It also fully eliminates any possibility of path traversal, given that uids are always integer values.

The issue was corrected in commit bfdbda22968e3de43fa8246cab1681cfd5d5493d.

Summary

Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the -U flag. This doesn't happen with the original sudo.

PoC

The initial test has been done in a container running Ubuntu 24.04 and installing oxidizr, running sudo-rs 0.2.2.

A user (bob) has been added with only ps command executable through sudo:

root    ALL=(ALL:ALL) ALL
bob     ALL=(ALL:ALL) /usr/bin/ps

The user is not able to read the /etc/sudoers file and running sudo -l -Uroot with original sudo (version 1.9.15p5) causes the following error:

Sorry, user bob is not allowed to execute 'list' as root on 43d4aed3cdbd.

The same command with sudo-rs is run without denying the execution:

User root may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) ALL

The same happens for other non-root users:

bob@43d4aed3cdbd:~$ sudo -l -Ufoo
User foo may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) /usr/bin/whoami

The behavior has been also been observed for version 0.2.5.

Impact

Users with limited sudo privileges can enumerate the sudoers file, revealing sensitive information about other users' permissions. Attackers can collect information that can be used to more targeted attacks.

Systems where users either do not have sudo privileges or have the ability to run all commands as root through sudo (the default configuration on most systems) are not affected by this advisory.

Credits

This issue was identified by Sonia Zorba.

Summary

Users with no (or very limited) sudo privileges can determine whether files exists in folders that they otherwise cannot access using sudo --list <pathname>.

PoC

As root:

# mkdir /tmp/foo
# chmod a-rwx /tmp/foo
# touch /tmp/foo/secret_file

As a user without any (or limited) sudo rights:

$ sudo --list /tmp/foo/nonexistent_file
sudo-rs: '/tmp/foo/nonexistent_file': command not found
$ $ sudo --list /tmp/foo/secret_file
sudo-rs: Sorry, user eve may not run sudo on host.

I.e. the user can distinguish whether files exist.

Related

Original sudo (vulnerable version tested by us: 1.9.15p5) exhibited similar behaviour for files with the executable bit set.

Impact

Users with local access to a machine can discover the existence/non-existence of certain files, revealing potentially sensitive information in the file names. This information can also be used in conjunction with other attacks.

Credits

This issue was identified by sudo-rs developer Marc Schoolderman

Impact

An issue was discovered where usernames containing the . and / characters could result in the corruption of specific files on the filesystem. As usernames are generally not limited by the characters they can contain, a username appearing to be a relative path can be constructed. For example we could add a user to the system containing the username ../../../../bin/cp. When logged in as a user with that name, that user could run sudo -K to clear their session record file. The session code then constructs the path to the session file by concatenating the username to the session file storage directory, resulting in a resolved path of /bin/cp. The code then clears that file, resulting in the cp binary effectively being removed from the system.

An attacker needs to be able to login as a user with a constructed username. Given that such a username is unlikely to exist on an existing system, they will also need to be able to create the users with the constructed usernames.

Patches

The bug is fixed in version 0.2.1 of sudo-rs. Sudo-rs now uses the uid for the user instead of their username for determining the filename. Note that an upgrade to this version will result in existing session files being ignored and users will be forced to re-authenticate. It also fully eliminates any possibility of path traversal, given that uids are always integer values.

The issue was corrected in commit bfdbda22968e3de43fa8246cab1681cfd5d5493d.

Summary

Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the -U flag. This doesn't happen with the original sudo.

PoC

The initial test has been done in a container running Ubuntu 24.04 and installing oxidizr, running sudo-rs 0.2.2.

A user (bob) has been added with only ps command executable through sudo:

root    ALL=(ALL:ALL) ALL
bob     ALL=(ALL:ALL) /usr/bin/ps

The user is not able to read the /etc/sudoers file and running sudo -l -Uroot with original sudo (version 1.9.15p5) causes the following error:

Sorry, user bob is not allowed to execute 'list' as root on 43d4aed3cdbd.

The same command with sudo-rs is run without denying the execution:

User root may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) ALL

The same happens for other non-root users:

bob@43d4aed3cdbd:~$ sudo -l -Ufoo
User foo may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) /usr/bin/whoami

The behavior has been also been observed for version 0.2.5.

Impact

Users with limited sudo privileges can enumerate the sudoers file, revealing sensitive information about other users' permissions. Attackers can collect information that can be used to more targeted attacks.

Systems where users either do not have sudo privileges or have the ability to run all commands as root through sudo (the default configuration on most systems) are not affected by this advisory.

Credits

This issue was identified by Sonia Zorba.

Summary

Users with no (or very limited) sudo privileges can determine whether files exists in folders that they otherwise cannot access using sudo --list <pathname>.

PoC

As root:

# mkdir /tmp/foo
# chmod a-rwx /tmp/foo
# touch /tmp/foo/secret_file

As a user without any (or limited) sudo rights:

$ sudo --list /tmp/foo/nonexistent_file
sudo-rs: '/tmp/foo/nonexistent_file': command not found
$ $ sudo --list /tmp/foo/secret_file
sudo-rs: Sorry, user eve may not run sudo on host.

I.e. the user can distinguish whether files exist.

Related

Original sudo (vulnerable version tested by us: 1.9.15p5) exhibited similar behaviour for files with the executable bit set.

Impact

Users with local access to a machine can discover the existence/non-existence of certain files, revealing potentially sensitive information in the file names. This information can also be used in conjunction with other attacks.

Credits

This issue was identified by sudo-rs developer Marc Schoolderman

Impact

An issue was discovered where usernames containing the . and / characters could result in the corruption of specific files on the filesystem. As usernames are generally not limited by the characters they can contain, a username appearing to be a relative path can be constructed. For example we could add a user to the system containing the username ../../../../bin/cp. When logged in as a user with that name, that user could run sudo -K to clear their session record file. The session code then constructs the path to the session file by concatenating the username to the session file storage directory, resulting in a resolved path of /bin/cp. The code then clears that file, resulting in the cp binary effectively being removed from the system.

An attacker needs to be able to login as a user with a constructed username. Given that such a username is unlikely to exist on an existing system, they will also need to be able to create the users with the constructed usernames.

Patches

The bug is fixed in version 0.2.1 of sudo-rs. Sudo-rs now uses the uid for the user instead of their username for determining the filename. Note that an upgrade to this version will result in existing session files being ignored and users will be forced to re-authenticate. It also fully eliminates any possibility of path traversal, given that uids are always integer values.

The issue was corrected in commit bfdbda22968e3de43fa8246cab1681cfd5d5493d.

Summary

Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the -U flag. This doesn't happen with the original sudo.

PoC

The initial test has been done in a container running Ubuntu 24.04 and installing oxidizr, running sudo-rs 0.2.2.

A user (bob) has been added with only ps command executable through sudo:

root    ALL=(ALL:ALL) ALL
bob     ALL=(ALL:ALL) /usr/bin/ps

The user is not able to read the /etc/sudoers file and running sudo -l -Uroot with original sudo (version 1.9.15p5) causes the following error:

Sorry, user bob is not allowed to execute 'list' as root on 43d4aed3cdbd.

The same command with sudo-rs is run without denying the execution:

User root may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) ALL

The same happens for other non-root users:

bob@43d4aed3cdbd:~$ sudo -l -Ufoo
User foo may run the following commands on 43d4aed3cdbd:
    (ALL : ALL) /usr/bin/whoami

The behavior has been also been observed for version 0.2.5.

Impact

Users with limited sudo privileges can enumerate the sudoers file, revealing sensitive information about other users' permissions. Attackers can collect information that can be used to more targeted attacks.

Systems where users either do not have sudo privileges or have the ability to run all commands as root through sudo (the default configuration on most systems) are not affected by this advisory.

Credits

This issue was identified by Sonia Zorba.

Summary

Users with no (or very limited) sudo privileges can determine whether files exists in folders that they otherwise cannot access using sudo --list <pathname>.

PoC

As root:

# mkdir /tmp/foo
# chmod a-rwx /tmp/foo
# touch /tmp/foo/secret_file

As a user without any (or limited) sudo rights:

$ sudo --list /tmp/foo/nonexistent_file
sudo-rs: '/tmp/foo/nonexistent_file': command not found
$ $ sudo --list /tmp/foo/secret_file
sudo-rs: Sorry, user eve may not run sudo on host.

I.e. the user can distinguish whether files exist.

Related

Original sudo (vulnerable version tested by us: 1.9.15p5) exhibited similar behaviour for files with the executable bit set.

Impact

Users with local access to a machine can discover the existence/non-existence of certain files, revealing potentially sensitive information in the file names. This information can also be used in conjunction with other attacks.

Credits

This issue was identified by sudo-rs developer Marc Schoolderman

Impact

An issue was discovered where usernames containing the . and / characters could result in the corruption of specific files on the filesystem. As usernames are generally not limited by the characters they can contain, a username appearing to be a relative path can be constructed. For example we could add a user to the system containing the username ../../../../bin/cp. When logged in as a user with that name, that user could run sudo -K to clear their session record file. The session code then constructs the path to the session file by concatenating the username to the session file storage directory, resulting in a resolved path of /bin/cp. The code then clears that file, resulting in the cp binary effectively being removed from the system.

An attacker needs to be able to login as a user with a constructed username. Given that such a username is unlikely to exist on an existing system, they will also need to be able to create the users with the constructed usernames.

Patches

The bug is fixed in version 0.2.1 of sudo-rs. Sudo-rs now uses the uid for the user instead of their username for determining the filename. Note that an upgrade to this version will result in existing session files being ignored and users will be forced to re-authenticate. It also fully eliminates any possibility of path traversal, given that uids are always integer values.

The issue was corrected in commit bfdbda22968e3de43fa8246cab1681cfd5d5493d.