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Linux-PAM: Privilege escalation


1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200909-01 / pam
Release Date September 07, 2009
Latest Revision September 07, 2009: 01
Impact normal
Exploitable remote
Package Vulnerable versions Unaffected versions Architecture(s)
sys-libs/pam < 1.0.4 >= 1.0.4 All supported architectures

Related bugreports: #261512


An error in the handling of user names of Linux-PAM might allow remote attackers to cause a Denial of Service or escalate privileges.

2.  Impact Information


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.


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.


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.

3.  Resolution Information


There is no known workaround at this time.


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

Code Listing 3.1: Resolution

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

4.  References


Page updated September 07, 2009

Summary: This is a Gentoo Linux Security Advisory

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