Tuesday April 2, 2002 Various Vulnerabilities in ZoneAlarm MailSafe ***************************************************** Scope ----------- Edvice recently tested ZoneLabs ZoneAlarm Pro ability to detect and quarantine incoming e-mail attachments that may contain malicious code or viruses. This functionality is provided by ZoneAlarm's MailSafe feature. The Findings -------------------- We encountered several vulnerabilities in ZoneAlarm 3.0 MailSafe. The vulnerabilities allow bypassing ZoneAlarm's e-mail protection. Details -------------- Most of the vulnerabilities we encountered are known Email Filters attack techniques and there is no point in explaining them again. However, there is one issue worth mentioning: It is possible to bypass ZoneAlarm Email Protection by appending a dot to the file name extension (e.g. malicious.exe becomes malicious.exe.). The dot changes the file name extension and MailSafe fails to compare it with known dangerous extensions. The MS-Windows operating system on the other hand disregards a dot at the end of a file name. When Windows is given a file name ending with a dot, it will automatically remove the dot from the file name extension. When Outlook or Outlook Express receives a file name that ends with a dot, it will present the dot, but will launch the appropriate application when the file is double-clicked, as if the dot does not exist. Vendor Status ---------------------- ZoneLabs was first contacted on January 26, 2002. A fix (v3.0.118) for most of the vulnerabilities we encountered, including the one mentioned above, is available through ZoneAlarm's Check for Update feature as from yesterday. ZoneLabs is still working on one of the vulnerabilities and a fix is expected soon. HTML Version: http://www.edvicesecurity.com/ad02-02.htm
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