Linux-PAM: Privilege escalation

Background

Linux-PAM (Pluggable Authentication Modules) is an architecture allowing the separation of the development of privilege granting software from the development of secure and appropriate authentication schemes.

Description

Marcus Granado repoted that Linux-PAM does not properly handle user names that contain Unicode characters. This is related to integer signedness errors in the pam_StrTok() function in libpam/pam_misc.c.

Impact

A remote attacker could exploit this vulnerability to cause a Denial of Service. A remote authenticated attacker could exploit this vulnerability to log in to a system with the account of a user that has a similar user name, but with non-ASCII characters.

Workaround

There is no known workaround at this time.

Resolution

All Linux-PAM users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=sys-libs/pam-1.0.4"