shadow: Privilege escalation

1. Gentoo Linux Security Advisory

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

Synopsis

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

2. Impact Information

Background

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

Description

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.

Impact

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

Workaround

There is no known workaround at this time.

Resolution

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

CVE-2006-1174

Updated June 07, 2006

Summary: This is a Gentoo Linux Security Advisory

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