Vulnerabilities

A vulnerability was found in PAM. The secret information is stored in memory, where the attacker can trigger the victim program to execute by sending characters to its standard input (stdin). As this occurs, the attacker can train the branch predictor to execute an ROP chain speculatively. This flaw could result in leaked passwords, such as those found in /etc/shadow while performing authentications.

linux-pam (aka Linux PAM) before 1.6.0 allows attackers to cause a denial of service (blocked login process) via mkfifo because the openat call (for protect_dir) lacks O_DIRECTORY.

The Linux-PAM package before 1.5.2-6.1 for openSUSE Tumbleweed allows authentication bypass for SSH logins. The pam_access.so module doesn't correctly restrict login if a user tries to connect from an IP address that is not resolvable via DNS. In such conditions, a user with denied access to a machine can still get access. NOTE: the relevance of this issue is largely limited to openSUSE Tumbleweed and openSUSE Factory; it does not affect Linux-PAM upstream.

A flaw was found in Linux-Pam in versions prior to 1.5.1 in the way it handle empty passwords for non-existing users. When the user doesn't exist PAM try to authenticate with root and in the case of an empty password it successfully authenticate.