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.
References
Summary
Users with limited sudo privileges (e.g. execution of a single command) can list sudo privileges of other users using the
-Uflag. 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:
The user is not able to read the
/etc/sudoersfile and runningsudo -l -Urootwith original sudo (version 1.9.15p5) causes the following error:The same command with sudo-rs is run without denying the execution:
The same happens for other non-root users:
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.
References