Shadow: Privilege escalation

1. Gentoo Linux Security Advisory

Package	Vulnerable versions	Unaffected versions	Architecture(s)
sys-apps/shadow	< 4.1.2.2	>= 4.1.2.2	All supported architectures

Related bugreports: #251320

An insecure temporary file usage in Shadow may allow local users to gain root privileges.

2. Impact Information

Shadow is a set of tools to deal with user accounts.

Paul Szabo reported a race condition in the "login" executable when setting up tty permissions.

A local attacker belonging to the "utmp" group could use symlink attacks to overwrite arbitrary files and possibly gain root privileges.

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-4.1.2.2"

4. References

Page updated March 10, 2009

Summary: This is a Gentoo Linux Security Advisory

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