CVE-2011-0609 - Adobe Flash Player ZeroDay

First information about new zero day in adobe flash player was published 03/11/2010 at
https://www.kidinhisroom.com/?q=content/us-cert-ewin-early-warning-indicator-new-adobe-flash-0-day-exploit

Then after 3 days Adobe confirmed bug and released advisory
http://www.adobe.com/support/security/advisories/apsa11-01.html


Filename: crsenvironscan.xls
Size:126,444 bytes
MD5 Hash: 4BB64C1DA2F73DA11F331A96D55D63E2

My analysis of  crsenvironscan.xls
There are no vulnerabilities in MS Office, there is a vulnerability in embeded swf as was described below.


1) There are embeded swf
(target file name f:\sm.swf)


This swf provide heap spray and then load second swf
view source code

it allocates memory
NOP Slide =14141414


then loads second swf.

2) second.swf consist bug

File created possibly by using a fuzzer from

addLabel.swf

looks like there are bugs exist when flash player attempts to parse a swf file.

Unknown opcode 152.
Unknown opcode 84. 

(detailed analysis will be provided soon) 

3) Shellcode

this is EmbededExec shellcode,not encrypted.

decompiled shellcode

Shellcode search for exe between

       cmp     dword ptr [eax], 47422E43h
       cmp     dword ptr [eax+4], 19890604h

hex code "432e424704068919" and

      cmp     dword ptr [eax], 4B635546h
      cmp     dword ptr [eax+4], 19820424h 

hex code "4655634b24048219"

if point view on this
as for me, that looks like some string and date

C.GB  1989/06/04    -  it may mean1989-06-04 Tiananmen, Beijing, China

FucK 1982/04/24    - ?

 
If you have any ideas, post in comments

Encryption of exe is interesting. 

First 4 bytes of exe header writed from shellcode

then encrypted date decrypts using this algo

 where eax - size of exe

decrypt: 

       xor     [ebx], al
       inc     ebx
       dec     eax
       inc     ebx
       dec     eax
       cmp     eax, 0 

       jmp  decrypt

This is for the first time I see such encryption in exploits found in the wild.

This is used to bypass scanners, which searches for the exe header.

4) Exe

a.exe 

size 46,048 bytes

MD5: 1e09970c9bf2ca08ee48f8b2e24f6c44

Download Payload File   a.exe 

pass: infected Virustotal 0/43

Information from PEiD InstallShield AFW [CAB SFX]

Sample download link
https://sites.google.com/site/villys777/crsenvironscan.zip
password : infected

Other samples you can get from Mila Parkour site:
http://contagiodump.blogspot.com/2011/03/cve-2011-0609-adobe-flash-player.html