I forwarded the Magic Byte message thread to Trend Micro and this was their response... they want me and my clients to upgrade to their latest version in order to get realistic protection... Anyone from Trend Micro listening? -----Original Message----- From: retail@xxxxxxxxxxxxxxxxxxxxxx [mailto:retail@xxxxxxxxxxxxxxxxxxxxxx] Sent: Saturday, October 29, 2005 4:02 AM To: auri@xxxxxxxx Subject: [SR #:1-40483753] RE: Update for the magic byte bug Dear Valued Client, Thank you for taking the time to contact and update us with this concern, I am Jonathan from the Consumer Support Team and I'll be assisting you on this matter. The issue you are inquiring about is already been addressed in the Trend Micro PC-Cillin Internet Security 2006 version. Hope this proves to be useful to you! Please let me know if we were able to resolve your concern(s) so we may formally close this case. Your immediate response will be most appreciated. Again, thank you for writing us. Should you have further inquiries, please do not hesitate to call us. Other means of reaching our office are indicated below. Please do not hesitate to contact us back should you have any further concern/s. NOTE: The Knowledge Base is a depository of information allowing users to get help in resolving any issue that may arise in using Trend Micro products. You can always visit the Knowledge Base website at this link <http://kb.trendmicro.com/solutions/solutionSearch.asp> Sincerely Yours, Jonathan Lua Consumer Support Team, Product Support Services TrendLabs HQ, Trend Micro Incorporated P.S. In order for us to have a history of our correspondence and help us process your inquiry faster, please DO NOT DELETE the subject and the contents of this email. The subject contains the case ID while the content serves as the case history. Are your products new pattern formats (NPF) compliant? Please see http://www.trendmicro.com/npf to verify product compliancy <<<====================================================>>> [URL / website] http://www.trendmicro.com/en/home/us/personal.htm [E-mail] pc-cillin@xxxxxxxxxxxxxxxxxxxxxx [Knowledge Base] http://kb.trendmicro.com/solutions/Default.asp? [Contact us] http://www.trendmicro.com/en/support/contact.htm [Retail Products] 1 - 800 - 864 - 6027 (from 5am to 5pm PST) <<<====================================================>>> If you have any comments with our support, please contact: Retail_manager@xxxxxxxxxxxxxxxxxxxxxx If you would like to voice out some of your comments about Trend and her products, please contact: comments@xxxxxxxxxxxxxxxxxxxxxx -----Original Message----- From: auri@xxxxxxxx Sent: 10/29/2005 09:26:34 AM To: "US Tech Support" <support@xxxxxxxxxxxxxx>; <info@xxxxxxxxxxxxxx> Subject: Update for the magic byte bug Is this being resolved in TM Internet Security 2005 please? Thanks again! Best, -Auri -----Original Message----- From: Andrey Bayora [mailto:andrey@xxxxxxxxxxxxxxx] Sent: Wednesday, October 26, 2005 2:27 PM To: full-disclosure@xxxxxxxxxxxxxxxxx Cc: bugtraq@xxxxxxxxxxxxxxxxx Subject: Update for the magic byte bug UPDATE, October 26, 2005 - Updated list of the vulnerable products. Multiple Vendor Anti-Virus Software Detection Evasion Vulnerability through forged magic byte. AUTHOR: Andrey Bayora (www.securityelf.org) For more details, screenshots and examples please read my article "The Magic of magic byte" at www.securityelf.org . In addition, you will find a sample "triple headed" program which has 3 different 'execution entry points', depending on the extension of the file (exe, html or eml) - just change the extension and the SAME file will be executed by (at least) THREE DIFFERENT programs! (thanks to contributing author Wayne Langlois from www.diamondcs.com.au). DATE: October 25, 2005 VULNERABLE vendors and software (tested): 1. ArcaVir 2005 (engine 2005-06-03,vir def 2005-06-27, scanner ver 2005-03-06, package ver 2005-06-21) 2. AVG 7 (updates 24 June, ver.7.0.323, virus base 267.8.0/27) 3. eTrust CA (ver 7.0.1.4, engine 11.9.1, vir sig. 9229) 4. Dr.Web (v.4.32b, update 27.06.2005) 5. F-Prot (ver. 3.16c, update 6/24/2005) 6. Ikarus (latest demo version for DOS) 7. Kaspersky (update 24 June, ver. 5.0.372) 8. McAfee Internet Security Suite 7.1.5 (updates 25 June, ver 9.1.08, engine 4.4.00, dat 4.0.4519 6/22/2005) 9. McAfee Corporate (updates 25 June, ver. 8.0.0 patch 10, vir def 4521, engine 4400) 10. Norman ( ver 5.81, engine 5.83.02, update 2005/06/23) 11. TrendMicro PC-Cillin 2005 (ver 12.0.1244, engine 7.510.1002, pattern 2.701.00) 12. TrendMicro OfficeScan (ver7.0, engine 7.510.1002, vir pattern 2.701.00 6/23/2005) 13. Panda Titanium 2005 (updates 24 June, ver 4.02.01) 14. UNA - Ukrainian National Antivirus (ver. 1.83.2.16 kernel v.265) 15. Sophos 3.91 (engine 2.28.4, virData 3.91) UPDATE, October 26, 2005 (based on the www.virustotal.com scan results, view the log at http://www.securityelf.org/updmagic.html) 16. CAT-QuickHeal (ver 8.0) 17. Fortinet (2.48.0.0) 18. TheHacker (5.8.4.128) IMPORTANT NOTE: Similar vulnerability may exist in many other antivirus\anti-spyware desktop and gateway products. In addition, various "file filter" solutions may be affected as well. NOT VULNERABLE vendors and software (tested): 1. F-Secure (updates 24 June, ver 5.56 b.10450) 2. Avast (ver. 4.6.655, vir databas 0525-5 06/25/2005) 3. BitDefender (ver. 8.0.200, update 6/24/2005, engine 7.01934) 4. ClamWin (ver. 0.86.1, upd 24 June 2005) 5. NOD32 (updates 24 June, ver 2.50.25, vir database 1.1152) 6. Symantec Corporate (ver 10.0.0.359, engine 103.0.2.7) 7. Norton Internet Security 2005 (ver 11.5.6.14) 8. VBA32 (ver 3.10.4, updates 27.06.2005) 9. HBEDV Antivir Personal (ver 6.31.00.01, engine 6.31.0.7, vir def 6.31.0.109 6/24/2005) 10. Sophos 5 (ver. 5.0.2, vir def 3.93, upd 6/30/2005) 11. Sophos 3.95 (engine 2.30.4) SEVERITY: critical DESCRIPTION: The problem exists in the scanning engine - in the routine that determines the file type. If some file types (file types tested are .BAT, .HTML and .EML) changed to have the MAGIC BYTE of the EXE files (MZ) at the beginning, then many antivirus programs will be unable to detect the malicious file. It will break the normal flow of the antivirus scanning and many existent and future viruses will be undetected. NOTE: In my test, I used the EXE headers (MZ), but it is possible to use other headers (magic byte) that will lead to the same effect. ANALYSIS: Some file types like .bat, .html and .eml can be properly executed even if they have some "unrelated" beginning. For example, in the case of .BAT files - it is possible to prepend some "junk" data at the beginning of the file without altering correct execution of the batch file. In my tests, I used the calc.exe headers (first 120 bytes - middle of the dosstub section) to change 5 different files of existing viruses. In addition, the simplest test of this vulnerability is to prepend only the magic byte (MZ) to the existing malicious file and check if this file is detected by antivirus program. NOTE, that this is NOT the case where the change of existing virus file resulted in the "broken" detection signature (see details and the test logic in "The Magic of magic byte" article at www.securityelf.org). WORKAROUND: I did not found any effective one besides of patching the vulnerable engine. CREDITS: The idea for this vulnerability came during discussions from Wayne Langlois at diamondcs.com.au, who hinted that JPEGs could probably be exploited in this way. TIME LINE: July 13, 2005 - Initial vendor notification July 16, 2005 - Second vendor notification .....Waiting.....Waiting.... October 24, 2005 - Public disclosure (uncoordinated) (lack of coordination from the vendors side) October 26, 2005 - Updated list of the vulnerable products.
