Summary
ARCServer is a backup and recovery management utility used to ensure high availability of critical applications and data.
Remote exploitation of a buffer overflow vulnerability in Computer Associates International Inc.'s (CA) BrightStor ARCserve Backup v11.5 may allow attackers to execute arbitrary code.
Credit:
The information has been provided by iDefense.
The original article can be found at: http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=467
Vulnerable Systems:
* CA BrightStor ARCServe Backup version 11.5 on Windows.
* Previous versions may also be affected.
The vulnerability exists within a DLL (ASCORE.dll) used by the the message engine process, msgeng.exe.
This process is responsible for handling RPC requests on TCP ports 6503 and 6504.
The vulnerability exists within the handler for opcode 47.
This opcode is used to run the PFC, preflight check, utility. PFC is used to run a series of checks on the server to test if any backup jobs might fail.
When parsing a request, the handler passes a user supplied buffer to the vsprintf() function without first validating the buffer size.
An attacker may leverage this to trigger an exploitable stack-based buffer overflow condition.
Exploitation allows unauthenticated attackers to execute arbitrary code with system-level privileges.
Exploitation requires that attackers send a malformed RPC request with opcode number 47. Exploitation is simple, as attackers can utilize SEH-based exploitation methods by triggering an exception when copying data past the end of the stack segment.
Workaround:
Employing firewalls to restrict access to the aforementioned ports will prevent the vulnerable code from being reached.
Vendor Status:
Computer Associates has addressed this vulnerability with patches to the vulnerable software.
For more information, please consult their advisory at the following URL.
http://supportconnectw.ca.com/public/storage/infodocs/babimpsec-notice.asp
