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Re: [Full-disclosure] 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


From: Rodrigo Barbosa <rodrigob () suespammers org>
Date: Tue, 15 Mar 2005 14:29:16 -0300

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On Tue, Mar 15, 2005 at 05:45:58PM +0100, Dr. Peter Bieringer wrote:
I STIL FIND IT happy to
see there are lot of AV out there that cant scan such
file properly to detect virus.

The problem must be located in the unzip engine:

We've created a mixed ZIP now:

# unzip -l mixed-eicar.zip
Archive:  mixed-eicar.zip
 Length     Date   Time    Name
--------    ----   ----    ----
     308  03-10-05 12:00   Test^G^[[2J^[[2;5m^[[1;31mHACKER 
ATTACK^[[2;25m^[[22;30m^[[3q.txt
     308  03-10-05 12:00   eicarcom2.zip
--------                   -------
     616                   2 files


BTW: note here that "unzip" displays the escape sequences very proper!

Available here:
<ftp://ftp.aerasec.de/pub/advisories/unfiltered-escape-sequences/mixed-eicar.zip>

Some AV software detect the virus only in second part of the ZIP file, so 
it looks like the first one is really skipped and not analysed.

F-Prot seems to detect it correctly:

VIRUS SIGNATURE FILES
SIGN.DEF created 13 March 2005
SIGN2.DEF created 13 March 2005
MACRO.DEF created 11 March 2005

Search: mixed-eicar.zip
Action: Report only
Files: "Dumb" scan of all files
Switches: -ARCHIVE -PACKED -SERVER

/home/rodrigob/tmp/mixed-eicar.zip->Test^G^[[2J^[[2;5m^[[1;31mHACKER 
ATTACK^[[2;25m^[[22;30m^[[3q.txt->eicar_c->eicar.com  Infection: EICAR_Test_File
/home/rodrigob/tmp/mixed-eicar.zip->eicarcom2.zip->eicar_com.zip->eicar.com  Infection: EICAR_Test_File

Results of virus scanning:

Files: 1
MBRs: 0
Boot sectors: 0
Objects scanned: 7
Infected: 2
Suspicious: 0
Disinfected: 0
Deleted: 0
Renamed: 0

Time: 0:00

- -- 
Rodrigo Barbosa <rodrigob () suespammers org>
"Quid quid Latine dictum sit, altum viditur"
"Be excellent to each other ..." - Bill & Ted (Wyld Stallyns)

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