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shadow: Privilege escalation


1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200606-02 / shadow
Release Date June 07, 2006
Latest Revision June 07, 2006: 01
Impact normal
Exploitable local
Package Vulnerable versions Unaffected versions Architecture(s)
sys-apps/shadow < 4.0.15-r2 >= 4.0.15-r2 All supported architectures

Related bugreports: #133615


A security issue in shadow allows a local user to perform certain actions with escalated privileges.

2.  Impact Information


shadow provides a set of utilities to deal with user accounts.


When the mailbox is created in useradd, the "open()" function does not receive the three arguments it expects while O_CREAT is present, which leads to random permissions on the created file, before fchmod() is executed.


Depending on the random permissions given to the mailbox file which is at this time owned by root, a local user may be able to open this file for reading or writing, or even executing it, maybe as the root user.

3.  Resolution Information


There is no known workaround at this time.


All shadow users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-apps/shadow-4.0.15-r2"

4.  References


Page updated June 07, 2006

Summary: This is a Gentoo Linux Security Advisory

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