This Metasploit module exploits a vulnerability on the lrFileIOService ActiveX, as installed with HP LoadRunner 11.50. The vulnerability exists in the WriteFileString method, which allow the user to write arbitrary files. It’s abused to drop a payload embedded in a dll, which is later loaded through the Init() method from the lrMdrvService control, by abusing an insecure LoadLibrary call. This Metasploit module has been tested successfully on IE8 on Windows XP. Virtualization based on the Low Integrity Process, on Windows Vista and 7, will stop this module because the DLL will be dropped to a virtualized folder, which isn’t used by LoadLibrary…. This Metasploit module exploits a vulnerability on the lrFileIOService ActiveX, as installed with HP LoadRunner 11.50. The vulnerability exists in the WriteFileString method, which allow the user to write arbitrary files. It’s abused to drop a payload embedded in a dll, which is later loaded through the Init() method from the lrMdrvService control, by abusing an insecure LoadLibrary call. This Metasploit module has been tested successfully on IE8 on Windows XP. Virtualization based on the Low Integrity Process, on Windows Vista and 7, will stop this module because the DLL will be dropped to a virtualized folder, which isn’t used by LoadLibrary.

Read more http://packetstormsecurity.com/files/123086/hp_loadrunner_writefilestring.rb.txt