REDHAT-BUG-1228571
First published: Fri Jun 05 2015(Updated: )
From the original report: "If SELinux is enabled, the _unix_run_helper_binary function in Linux-PAM 1.1.8 and earlier hangs indefinitely when verifying a password of 65536 characters, which allows attackers to conduct username enumeration and denial of service attacks. When supplying a password of 65536 characters or more, the process will block on the write(2) call at modules/pam_unix/support.c:614 because it tries to write strlen(passwd)+1 bytes to a blocking pipe and a pipe has a limited capacity of 65536 bytes on Linux." Acknowledgements: Red Hat would like to thank Sebastien Macke of Trustwave SpiderLabs for reporting this issue.
| Affected Software | Affected Version | How to fix |
|---|---|---|
| SUSE PAM | <=1.1.8 |
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Reference Links
- https://bugzilla.redhat.com/show_bug.cgi/attachment.cgi?id=1038860&action=diff
- https://bugzilla.redhat.com/show_bug.cgi/attachment.cgi?id=1038860&action=edit
- http://www.openwall.com/lists/oss-security/2015/06/25/13
- https://rhn.redhat.com/errata/RHSA-2015-1640.html
- https://bugzilla.redhat.com/show_bug.cgi?id=1228571
Frequently Asked Questions
What is the severity of REDHAT-BUG-1228571?
The vulnerability REDHAT-BUG-1228571 allows for potential username enumeration and denial of service attacks.
How do I fix REDHAT-BUG-1228571?
To resolve REDHAT-BUG-1228571, upgrade Linux-PAM to version 1.1.9 or later.
What causes REDHAT-BUG-1228571?
REDHAT-BUG-1228571 is caused by the _unix_run_helper_binary function hanging indefinitely with excessively long passwords.
Who is affected by REDHAT-BUG-1228571?
Any system using Linux-PAM version 1.1.8 or earlier with SELinux enabled is vulnerable to REDHAT-BUG-1228571.
What impacts does REDHAT-BUG-1228571 have on systems?
The main impacts of REDHAT-BUG-1228571 include potential denial of service and increased risk of username enumeration.
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- canonical/suse pam