SB2013110802 - Permissions, Privileges, and Access Controls in OpenSSH

Description

This security bulletin contains information about 1 vulnerability.

1) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2013-4548)

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a remote #AU# to read and manipulate data.

The mm_newkeys_from_blob function in monitor_wrap.c in sshd in OpenSSH 6.2 and 6.3, when an AES-GCM cipher is used, does not properly initialize memory for a MAC context data structure, which allows remote authenticated users to bypass intended ForceCommand and login-shell restrictions via packet data that provides a crafted callback address.

Remediation

Install update from vendor's website.

References

• http://lists.opensuse.org/opensuse-security-announce/2013-11/msg00017.html
• http://marc.info/?l=bugtraq&m=141576985122836&w=2
• http://openwall.com/lists/oss-security/2013/11/08/3
• http://www.openssh.com/txt/gcmrekey.adv
• http://www.ubuntu.com/usn/USN-2014-1