CVE-2013-4122

Published: 18 July 2013

Cyrus SASL 2.1.23, 2.1.26, and earlier does not properly handle when a NULL value is returned upon an error by the crypt function as implemented in glibc 2.17 and later, which allows remote attackers to cause a denial of service (thread crash and consumption) via (1) an invalid salt or, when FIPS-140 is enabled, a (2) DES or (3) MD5 encrypted password, which triggers a NULL pointer dereference.

Notes

NULL return from crypt() if the salt isn't sane
Upgraded to medium, bug report shows remote attackers can disable
the sasl service by repeating the attack; THREADS=0 configuration is a
work-around that may help to prevent abuse.

eglibc only returns NULL from crypt() in 2.17+, so quantal
and older are not affected.
2015-09-25: patch was dropped by mistake in debian's
2.1.26 package, fixed again in 2.1.26.dfsg1-14

Status

References

• http://openwall.com/lists/oss-security/2013/07/12/3
• http://git.cyrusimap.org/cyrus-sasl/commit/?id=dedad73e5e7a75d01a5f3d5a6702ab8ccd2ff40d
• https://ubuntu.com/security/notices/USN-1988-1
• https://ubuntu.com/security/notices/USN-2755-1
• https://www.cve.org/CVERecord?id=CVE-2013-4122
• NVD
• Launchpad
• Debian

Bugs

• http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=716835
• https://bugs.launchpad.net/ubuntu/+source/cyrus-sasl2/+bug/1187001