Unknown vulnerability in the passwdcheck function in Shadow 4.0.4.1, and possibly other versions before 4.0.5, allows local users to conduct unauthorized activities when an error from a pamchauthtok function call is not properly handled.

Quoting first paragraph from [1]: https://bugzilla.redhat.com/showbug.cgi?id=173008

for issue description: ====================== When starting a program via "su - user -c program" the user session can escape to the parent session by using the TIOCSTI ioctl to push characters into the input buffer. This allows for example a non-root session to push "chmod 666 /etc/shadow" or similarly bad commands into the input buffer such that after the end of the session they are executed.

References: [1] https://bugzilla.redhat.com/showbug.cgi?id=173008 [2] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=628843

useradd in shadow-utils before 4.0.3, and possibly other versions before 4.0.8, does not provide a required argument to the open function when creating a new user mailbox, which causes the mailbox to be created with unpredictable permissions and possibly allows attackers to read or modify the mailbox.

shadow: TOCTOU (time-of-check time-of-use) race condition when copying and removing directory trees