HP OpenView Network Node Manager ovwebsnmpsrv.exe Unrecognized Option Buffer Overflow

Description

This module exploits a stack buffer overflow in HP OpenView Network Node Manager 7.53 prior to NNM_01203. By specifying a long 'arg' parameter when executing the 'jovgraph.exe' CGI program, an attacker can cause a stack-based buffer overflow and execute arbitrary code. The vulnerable code is within the option parsing function within "ovwebsnmpsrv.exe" with a timestamp prior to April 7th, 2010.

Reaching the vulnerable code requires a 'POST' request with an 'arg' parameter that, when combined with some static text, exceeds 10240 bytes. The parameter must begin with a dash. It is important to note that this vulnerability must be exploited by overwriting SEH. This is since overflowing the buffer with controllable data always triggers an access violation when attempting to write static text beyond the end of the stack.

Exploiting this issue is a bit tricky due to a restrictive character set. In order to accomplish arbitrary code execution, a double-backward jump is used in combination with the Alpha2 encoder.