CVE-2021-3156 "Baron Samedit"

Sudo before 1.9.5p2 contains an off-by-one error that can result in a heap-based buffer overflow, which allows privilege escalation to root via “sudoedit -s” and a command-line argument that ends with a single backslash character.

Recent assessments:

cdelafuente-r7 at January 27, 2021 3:40pm UTC reported:

Sudo is vulnerable to a local privilege escalation that enables any local user to gain root privileges. This is due to a heap-based buffer overflow when unescaping backslashes in the command’s arguments. This vulnerable code has been introduced in July 2011. According to the advisory, legacy versions from 1.8.2 to 1.8.31p2 and stable versions from 1.9.0 to 1.9.5p1 are vulnerable in their default configurations. Note that the local user password is not required to successfully exploit this vulnerability.

The exploitation is done by invoking “sudoedit -s” command to reach the vulnerable code and do an out-of-bounds write in heap memory. The security researchers were able to exploit this vulnerability and get a shell as root using 3 different methods. One of them, which seems to be the easiest and the most reliable, is demo’ed in this video.

I couldn’t find any PoC available, but there are enough technical details in the advisory to write an exploit. It is a critical bug and sudo should be patched immediately. It is very likely a working exploit will be publicly available soon.

MadDud at January 30, 2021 9:59am UTC reported:

Sudo is vulnerable to a local privilege escalation that enables any local user to gain root privileges. This is due to a heap-based buffer overflow when unescaping backslashes in the command’s arguments. This vulnerable code has been introduced in July 2011. According to the advisory, legacy versions from 1.8.2 to 1.8.31p2 and stable versions from 1.9.0 to 1.9.5p1 are vulnerable in their default configurations. Note that the local user password is not required to successfully exploit this vulnerability.

The exploitation is done by invoking “sudoedit -s” command to reach the vulnerable code and do an out-of-bounds write in heap memory. The security researchers were able to exploit this vulnerability and get a shell as root using 3 different methods. One of them, which seems to be the easiest and the most reliable, is demo’ed in this video.

I couldn’t find any PoC available, but there are enough technical details in the advisory to write an exploit. It is a critical bug and sudo should be patched immediately. It is very likely a working exploit will be publicly available soon.

dorpor412 at January 27, 2021 8:10am UTC reported:

Sudo is vulnerable to a local privilege escalation that enables any local user to gain root privileges. This is due to a heap-based buffer overflow when unescaping backslashes in the command’s arguments. This vulnerable code has been introduced in July 2011. According to the advisory, legacy versions from 1.8.2 to 1.8.31p2 and stable versions from 1.9.0 to 1.9.5p1 are vulnerable in their default configurations. Note that the local user password is not required to successfully exploit this vulnerability.

The exploitation is done by invoking “sudoedit -s” command to reach the vulnerable code and do an out-of-bounds write in heap memory. The security researchers were able to exploit this vulnerability and get a shell as root using 3 different methods. One of them, which seems to be the easiest and the most reliable, is demo’ed in this video.

I couldn’t find any PoC available, but there are enough technical details in the advisory to write an exploit. It is a critical bug and sudo should be patched immediately. It is very likely a working exploit will be publicly available soon.

marshalcn at January 27, 2021 6:16am UTC reported:

Sudo is vulnerable to a local privilege escalation that enables any local user to gain root privileges. This is due to a heap-based buffer overflow when unescaping backslashes in the command’s arguments. This vulnerable code has been introduced in July 2011. According to the advisory, legacy versions from 1.8.2 to 1.8.31p2 and stable versions from 1.9.0 to 1.9.5p1 are vulnerable in their default configurations. Note that the local user password is not required to successfully exploit this vulnerability.

The exploitation is done by invoking “sudoedit -s” command to reach the vulnerable code and do an out-of-bounds write in heap memory. The security researchers were able to exploit this vulnerability and get a shell as root using 3 different methods. One of them, which seems to be the easiest and the most reliable, is demo’ed in this video.

I couldn’t find any PoC available, but there are enough technical details in the advisory to write an exploit. It is a critical bug and sudo should be patched immediately. It is very likely a working exploit will be publicly available soon.

Assessed Attacker Value: 5
Assessed Attacker Value: 5Assessed Attacker Value: 5