libspf2: DNS response buffer overflow

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200810-03 / libspf2
Release Date	October 30, 2008
Latest Revision	October 30, 2008: 01
Impact	high
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
mail-filter/libspf2	< 1.2.8	>= 1.2.8	All supported architectures

Related bugreports: #242254

Synopsis

A memory management error in libspf2 might allow for remote execution of arbitrary code.

2. Impact Information

Background

libspf2 is a library that implements the Sender Policy Framework, allowing mail transfer agents to make sure that an email is authorized by the domain name that it is coming from. Currently, only the exim MTA uses libspf2 in Gentoo.

Description

libspf2 uses a fixed-length buffer to receive DNS responses and does not properly check the length of TXT records, leading to buffer overflows.

Impact

A remote attacker could store a specially crafted DNS entry and entice a user or automated system using libspf2 to lookup that SPF entry (e.g. by sending an email to the MTA), possibly allowing for the execution of arbitrary code.

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All libspf2 users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=mail-filter/libspf2-1.2.8"

4. References

CVE-2008-2469

Page updated October 30, 2008

Summary: This is a Gentoo Linux Security Advisory

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