Re: [Full-Disclosure] Exploiting Multiple Flaws in Symantec Antivirus 2004 for Windows Mobile

[Sym Security <symsecurity@xxxxxxxxxxxx>]

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Symantec's response to Issue #1: Symantec's Auto-Protect feature in Symantec 
AntiVirus for Handhelds 
scanner is designed to detect malicious code, in real time, as files are 
saved to a device. At this time the anticipated mechanism for transport to 
a Pocket PC is via the file system, which is scanned in real-time by 
Symantec AntiVirus for Handhelds: for malicious code to be loaded into 
memory, it would have to be downloaded/synchronized/saved to the device 
first, and it would first be detected by Auto-Protect in Symantec 
AntiVirus for Handhelds. 


Symantec's response to Issue #2: Symantec AntiVirus for Handhelds does have 
the ability to detect a byte 
stream anywhere in a file ? but the suggested scenario is altering the 
eicar string such that it no longer is an eicar string. Therefore Symantec 
AntiVirus for Handhelds does not recognize it, not because it can't match 
the string, but because the string itself has been modified. Additionally, 
the current eicar definition (as defined by eicar.org) concedes to 
efficiency and does not require detection at any point in any file.



On Tuesday 16 September 2003 07:59 pm, auto9115@xxxxxxxxxxxx wrote:
> Exploiting Multiple Flaws in Symantec Antivirus 2004 for Windows Mobile
> Version tested: 3.0.0.194 (latest version)
> Date: Sept. 13, 2003
>
> Background: Viruses have started to show up on Personal Data Assistants
> (PDAs) and handheld wireless devices. Although there are currently no
> viruses in the wild that infect the Windows CE operating system, may
> companies have released virus scanners for Windows Mobile (formerly
> PocketPC). Examples include PC-cillin, Airscanner, F-secure, and McAfee.
> Since McAfee was recently selected to go OEM on all new Dell Axim
> handhelds, Symantec scrambled to get a product out. They have just released
> their final version (available for $39.99 for a one year license), but
> unfortunately, in the scramble to release it they apparently forgot to test
> it to see if it is working ;)
>
> Vulnerability #1: Real-time scanning appears to not work.
>
> Symantec is currently the only AV company that claims to do real-time
> scanning in the background on Windows CE. This claim gives them a
> significant market advantage.  However, we can see that it is not true
> real-time scanning. For example, if the scanner is active in memory and you
> open the famous Eicar test virus (eicar.exe) into RAM, the scanner does not
> detect it. It is not until you "save" a copy of a file with the Eicar to
> your file system does Symantec detect it.  So it is not real-time scanning
> of viral code, but rather just a simple monitor to activate a scan any time
> a file is saved.  Therefore, this does not protect against hostile code
> active in RAM.
>
> Vulnerability #2: The Virus scanner does not appear to work at all!
>
> Like any antivirus scanner, Symantec detects the Eicar test virus
> (eicar.exe or eicar.txt). At least, at first glance it appears to detect
> it. However, you can easily defeat this by adding a few bytes of random
> text before or after the Eicar string.  For example, if you use a hex/text
> editor to add a few random bytes of text before and after the string, then
> Symantec won't detect it!  However, other AVs easily detect it, as they
> should. An AV scanner should be able to detect a byte stream anywhere in
> the file, but Symantec is easily bypassed with this rudimentary trick.
>
> These exploits have not been submitted to Bugtraq, since that mailing
> list is now owned by  Symantec, and they have more "selective" full
> disclosure than this list.
>
> Don Cheatham
> Wireless Network Engineer
>
>
>
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Sym Security
Symantec Corporation
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