Unfiltered escape sequences in filenames contained in ZIP archives wouldn't be escaped on displaying or logging, and can also lead to bypass AV scanning

["Dr. Peter Bieringer" <pbieringer () aerasec de>]

Hello,

during investigation of Sober.l we got the idea to replace the spaces of a 
filename contained in the ZIP archive by some escape sequences.

Many AV software is logging such filenames during decompressing, so after 
creating such regular ZIP archive (by using Perl Archive::Zip module, no 
other tweaks!) we've found that some of the tested products do not filter 
or replace the escape sequences, which leads to funny results during 
displaying the output of the AV scanner or viewing the log.

Also we found that at least 2 AV scan programs from 2 vendors do not detect 
the virus inside and report "clean" instead.

See here for more details:

<ftp://ftp.aerasec.de/pub/advisories/unfiltered-escape-sequences/unfiltered-escape-sequences.txt>
<http://www.aerasec.de/security/index.html?id=ae-200503-020&lang=en>

We provide also samples and the Perl program for creating the samples:
<ftp://ftp.aerasec.de/pub/advisories/unfiltered-escape-sequences/>


Due lack of time we only tested a few products, so if one can provide 
results of other products, pls. send them (also) to us. Thank you!

Regards,
        Dr. Peter Bieringer
--
Dr. Peter Bieringer                             Phone: +49-8102-895190
AERAsec Network Services and Security GmbH        Fax: +49-8102-895199
Wagenberger Strasse 1                          Mobile: +49-174-9015046
D-85662 Hohenbrunn                       E-Mail: pbieringer () aerasec de
Germany                                Internet: http://www.aerasec.de

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