1. OVERVIEW The Brava PDF Reader application is vulnerable to Insecure DLL Hijacking Vulnerability. Similar terms that describe this vulnerability have been come up with Remote Binary Planting, and Insecure DLL Loading/Injection/Hijacking/Preloading. 2. PRODUCT DESCRIPTION Brava! Reader is a free application that views and prints TIFF, PDF, XPS and secure CSF (Content Sealed Format) files created by other Brava products or the Net-It publishing products. Brava Reader is simple to use and runs as a desktop program or as an ActiveX component in a web page. 3. VULNERABILITY DESCRIPTION The Brava PDF Reader application passes an insufficiently qualified path in loading its external library - "dwmapi.dll" when a user opens its associated file with extensions - csf, pdf, sid, tiff, tif, xdl, xps . 4. VERSIONS AFFECTED 3.3.0.18 and (probably) lower version 5. PROOF-OF-CONCEPT/EXPLOIT http://core.yehg.net/lab/pr0js/advisories/dll_hijacking/brava_pdf_reader/poc/movie/brava_pdf_reader_3.3.0.18-dll-hijacking.mp4 http://core.yehg.net/lab/pr0js/advisories/dll_hijacking/brava_pdf_reader/poc/brava_pdf_reader_3.3.0.18-dll-hijacking-poc.zip Tested Platform: Windows XP Service Pack 3 (Fresh Windows) 6. IMPACT Attackers can trigger a successful exploit against a victim user in a number of ways such as placing a malicious external library file made as hidden attribute and a seemingly interesting file in network shares, usb drives, file sharing networks, social networks, ..etc 7. SOLUTION Fixed version from the vendor has not been released yet. However, it is suggested that the following workarounds be deployed by users to protect increasing mass exploitation of this vulnerability class: - Disable loading of libraries from WebDAV and remote network shares - Disable the WebClient service Please see workaround solution links in References section. 8. VENDOR Informative Graphics Corporation http://www.bravaviewer.com/reader.htm 9. CREDIT This vulnerability was discovered by Aung Khant, http://yehg.net, YGN Ethical Hacker Group, Myanmar. 10. DISCLOSURE TIME-LINE 09-11-2010: notified vendor 09-13-2010: vulnerability disclosed 11. REFERENCES Original Advisory URL: http://core.yehg.net/lab/pr0js/advisories/dll_hijacking/[brava_pdf_reader]_3.3.0.18_insecure_dll_hijacking Workaround Solution: http://support.microsoft.com/kb/2264107 Workaround Solution: https://www.microsoft.com/technet/security/advisory/2269637.mspx#EGF Developer Solution: http://msdn.microsoft.com/en-us/library/ff919712%28v=VS.85%29.aspx Unofficial DLL Hijacking List: http://www.corelan.be:8800/index.php/2010/08/25/dll-hijacking-kb-2269637-the-unofficial-list/ Testing for DLL Hijacking: http://core.yehg.net/lab/pr0js/view.php/when_testing_for_dll_hijacking.txt #yehg [09-13-2010] _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/