ESA-2013-003: EMC Avamar Client Elevation of Privilege Vulnerability
EMC Identifier: ESA-2013-003
CVE Identifier: CVE-2012-2291
Severity Rating: CVSS v2 Base Score: 6.8 (AV:L/AC:L/Au:S/C:C/I:C/A:C)
Affected Products:
EMC Avamar HP-UX Client 4.x, 5.x and 6.x
EMC Avamar Mac OS Client 4.x, 5.x and 6.x
EMC Avamar Plugin for Oracle 4.x, 5.x and 6.x
Note: Other Linux and Unix Avamar client systems could also be affected as a result of a support or locally-performed procedure that incorrectly sets the permission of the Avamar var directory (/usr/local/avamar/var or /opt/AVMRclnt/var).
Summary:
Due to a vulnerability, described in detail below, the Avamar client leaves certain directories and files as world writable. The presence of world writable directories and files may inadvertently result in elevation of privileges by a user who has access to the local file system.
Details:
The Avamar affected client process runs as root and after each backup it leaves the cache files as world readable and writable. While the cache files themselves do not contain sensitive information, when the parent directory is world-writable, the cache files could be used by an attacker to elevate the privileges when a system-level backup is performed. The non-root user can create symbolic links to obtain unauthorized access to files on the affected system.
Note: This vulnerability information is currently public. EMC is not aware of any instance in which the vulnerability has been exploited maliciously.
Resolution:
The following workaround steps must be performed to mitigate the risk until the full fix is available from EMC.
For HP-UX clients:
The permissions of the /opt/AVMRclnt/var directory should be set to 0755.
Log into the HP-UX client as the root user and type the following command:
chmod 0755 /opt/AVMRclnt/var
For Mac OS clients:
The permissions of the /var/avamar directory should be set to 0755.
Log into the Mac client as the root user and type the following command:
chmod 0755 /var/avamar
For Oracle clients:
The following procedure only applies to clients where the directory permissions of the Avamar var directory (/usr/local/avamar/var or /opt/AVMRclnt/var) have been manually changed after installation of the Avamar plugin for Oracle:
The permissions of the /usr/local/avamar/var should be set to 0775 with the group ownership set to the oracle group. Log into the Oracle client as the root user and type either of the following pairs of commands:
On Linux and Unix Oracle clients other than Solaris and HP-UX:
chmod 0775 /usr/local/avamar/var
chgrp oracle /usr/local/avamar/var
On Solaris and HP-UX Oracle clients:
chmod 0775 /opt/AVMRclnt/var
chgrp oracle /opt/AVMRclnt/var
Other Avamar clients:
Verify that the permissions of the Avamar var directory (/usr/local/avamar/var or /opt/AVMRclnt/var) on Linux and Unix clients are not modified as a result of a support or locally-performed procedure. The permissions should be set to 0755.
If you have any questions or concerns about running the above commands please contact EMC Technical Support at http://www.emc.com/contact.
Read and use the information in this EMC Security Advisory to assist in avoiding any situation that might arise from the problems described herein. If you have any questions regarding this product alert, contact EMC Software Technical Support at 1-877-534-2867.
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For an explanation of Severity Ratings, refer to EMC Knowledgebase solution emc218831. EMC recommends all customers take into account both the base score and any relevant temporal and environmental scores which may impact the potential severity associated with particular security vulnerability.
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