CVE-2021-3156

Отчет

This flaw does not affect the versions of sudo shipped with Red Hat Enterprise Linux 5, because the vulnerable code was not present in these versions.

Меры по смягчению последствий

Red Hat Product Security strongly recommends customers to update to fixed sudo packages once they are available. For customers who cannot update immediately, the following interim partial mitigation using systemtap is suggested:

1. Install required systemtap packages and dependencies:

Then for RHEL 7 install kernel debuginfo, using:

Then for RHEL 8 & 6 install sudo debuginfo, using:

2. Create the following systemtap script: (call the file as sudoedit-block.stap)

3. Install the script using the following command: (using root)

(This should output the PID number of the systemtap script) This script will cause the vulnerable sudoedit binary to stop working. The sudo command will still work as usual. The above change does not persist across reboots and must be applied after each reboot. Please consult How to make a systemtap kernel module load persistently across reboots? (https://access.redhat.com/solutions/5752521) to learn how to turn this into a service managed by initd. 4. Once the new fixed packages are installed, the systemtap script can be removed by killing the systemtap process. For example, by using:

(where 7590 is the PID of the systemtap process)