Summary ======= There is a file handling DoS in GIMP (the GNU Image Manipulation Program) for the 'fit' file format affecting all versions (Windows and Linux) up to and including 2.8.0. A file in the fit format with a malformed 'XTENSION' header will cause a crash in the GIMP program. CVE number: CVE-2012-3236 Vendor Homepage: http://www.gimp.org/ Date reported to vendor: 25/05/2012 Found by Joseph Sheridan: href="http://www.reactionpenetrationtesting.co.uk/joseph-sheridan.html This advisory is posted at: http://www.reactionpenetrationtesting.co.uk/FIT-file-handling-DoS.html PoC file is available here: http://www.reactionpenetrationtesting.co.uk/vuln.fit Affected Products ================= Vulnerable Products +------------------ The following products are known to be affected by this vulnerability: * GIMP <= 2.8.0 (Windows or Linux builds) Products Not Vulnerable +-------------------------------- * GIMP 2.8.1 Details ======= There is a file handling DoS in GIMP (the GNU Image Manipulation Program) for the 'fit' file format affecting all versions (Windows and Linux) up to 2.8.0. A file in the fit format with a malformed 'XTENSION' header will cause a crash in the GIMP program. The flaw is triggered by opening a crafted 'fit' file or allowing the file explorer dialog to preview the file. A file in the fit format starting as follows will trigger the crash: XTENSIONaaaaaaaaaaaaaaaaaaaaaa...aaaaaaaaaaaaaaaaaaaaaaaaHEADER2... The vulnerable code is in the fits-io.c lines where the program attempts to copy from a null pointer: { fdat = fits_decode_card (fits_search_card (hdr, "XTENSION"), typ_fstring); strcpy (hdulist->xtension, fdat->fstring); } This code can be patched by changing it to the following (as GIMP 2.8.1): fdat = fits_decode_card (fits_search_card (hdr, "XTENSION"), typ_fstring); if(fdat != NULL) { strcpy (hdulist->xtension, fdat->fstring); } else { strcpy (errmsg, "No valid XTENSION header found."); goto err_return; } Impact ====== Successful exploitation of the vulnerability may result in an application crash and denial of service. Solution =========== The GIMP team have provided an update for this issue (release 2.8.1). Workarounds =========== The fits-io.c file can be patched as above. Distribution ============ In addition to posting on the website, a text version of this notice is posted to the following e-mail and Usenet news recipients. * bugtraq () securityfocus com * full-disclosure () lists grok org uk * oss [dash] security [dash] subscribe [at] lists [dot] openwall [dot] com Future updates of this advisory, if any, will be placed on the ReactionIS corporate website, but may or may not be actively announced on mailing lists or newsgroups. Users concerned about this problem are encouraged to check the URL below for any updates: http://www.reactionpenetrationtesting.co.uk/FIT-file-handling-DoS.html ============================================================================ Reaction Information Security Lombard House Business Centre, Suite 117, 12-17 Upper Bridge Street, Canterbury, Kent, CT1 2NF Phone: +44 (0)1227 785050 Email: research () reactionis {dot} co {dot} uk Web: http://www.reactionpenetrationtesting.co.uk