A serious security violation in PAM was discovered.
Disabled passwords (i.e. those with '*' in the
password file) were classified as empty password and access to such
accounts is granted through the regular login procedure (getty,
telnet, ssh). This works for all such accounts whose shell field in
the password file does not refer to /bin/false.
Only version 0.76 of PAM seems to be affected by this problem.
This problem has been fixed in version 0.76-6 for the current unstable distribution (sid). The stable distribution (woody), the old stable distribution (potato) and the testing distribution (sarge) are not affected by this problem.
As stated in the Debian security team FAQ, testing and unstable are rapidly moving targets and the security team does not have the resources needed to properly support those. This security advisory is an exception to that rule, due to the seriousness of the problem.
We recommend that you upgrade your PAM packages immediately if you are running Debian/unstable.
MD5 checksums of the listed files are available in the original advisory.