USN-3276-2: shadow regression

Releases

• Ubuntu 17.04
• Ubuntu 16.10
• Ubuntu 16.04 ESM
• Ubuntu 14.04 ESM

Packages

• shadow - system login tools

Details

USN-3276-1 intended to fix a vulnerability in su. The solution introduced
a regression in su signal handling. This update modifies the security fix.
We apologize for the inconvenience.

Original advisory details:

Sebastian Krahmer discovered integer overflows in shadow utilities.
A local attacker could possibly cause them to crash or potentially
gain privileges via crafted input. (CVE-2016-6252)

Tobias Stöckmann discovered a race condition in su. A local
attacker could cause su to send SIGKILL to other processes with
root privileges. (CVE-2017-2616)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 17.04

• login - 1:4.2-3.2ubuntu1.17.04.2
• passwd - 1:4.2-3.2ubuntu1.17.04.2
• uidmap - 1:4.2-3.2ubuntu1.17.04.2

Ubuntu 16.10

• login - 1:4.2-3.2ubuntu1.16.10.2
• passwd - 1:4.2-3.2ubuntu1.16.10.2
• uidmap - 1:4.2-3.2ubuntu1.16.10.2

Ubuntu 16.04

• login - 1:4.2-3.1ubuntu5.3
• passwd - 1:4.2-3.1ubuntu5.3
• uidmap - 1:4.2-3.1ubuntu5.3

Ubuntu 14.04

• login - 1:4.1.5.1-1ubuntu9.5
• passwd - 1:4.1.5.1-1ubuntu9.5
• uidmap - 1:4.1.5.1-1ubuntu9.5

In general, a standard system update will make all the necessary changes.

References

• https://launchpad.net/bugs/1690820