FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

serf -- SSL Certificate Null Byte Poisoning

Affected packages
serf < 1.3.7

Details

VuXML ID 69048656-2187-11e4-802c-20cf30e32f6d
Discovery 2014-08-06
Entry 2014-08-11

serf Development list reports:

Serf provides APIs to retrieve information about a certificate. These APIs return the information as NUL terminated strings (commonly called C strings). X.509 uses counted length strings which may include a NUL byte. This means that a library user will interpret any information as ending upon seeing this NUL byte and will only see a partial value for that field.

Attackers could exploit this vulnerability to create a certificate that a client will accept for a different hostname than the full certificate is actually for by embedding a NUL byte in the certificate.

This can lead to a man-in-the-middle attack. There are no known instances of this problem being exploited in the wild and in practice it should be difficult to actually exploit this vulnerability.

References

CVE Name CVE-2014-3504