[NEWS] IDA Pro Format String Vulnerability

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  IDA Pro Format String Vulnerability
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SUMMARY

"The  <http://www.datarescue.com/> IDA Pro Disassembler and Debugger is an 
interactive, programmable, extensible, muti-processor disassembler hosted 
on Windows or on Linux". IDA Pro is vulnerable to format string 
vulnerability parsing a loaded DLL name.

DETAILS

Vulnerable Systems:
 * IDA Pro version 4.7.0.830

The problem exist when IDA Debugger tries to write informations about 
loaded dynamic link library (when LOAD_DLL_DEBUG_EVENT / 
UNLOAD_DLL_DEBUG_EVENT occurs)

Lets look at following sample code to get a better view:
       call a
       db "KERNEL32.DLL",0
       a:
       call LoadLibraryA
       int 3

The code above should return KERNEL32.DLL base stored in EAX register. IDA 
Debugger shows EAX as: "EAX=77E60000 -> kernel32.dll:77E60000" (general 
registers window) - this is one of the examples. However when loaded 
library name includes special format specifiers the vulnerability takes 
place, here is the vulnerable code:
 (disassembly of ida.wll)
       .text:012563F8 mov esi, [ebp+arg_0]
       .text:012563FB push [ebp+arg_C]
       .text:012563FE push dword_12A27C4
       .text:01256404 push 0
       .text:01256406 push ebx ; format string
       .text:01256407 lea eax, [ebp+arg_0]
       .text:0125640A push eax
       .text:0125640B push offset sub_12562C0
       .text:01256410 call sub_011D1C78 ; parser

Where EBX contains format specifier supplied by attacker.

This vulnerability after successful exploitation can allow the attacker to 
run arbitrary code in context of current user. Of course if the 
exploitation was not successful IDA Debugger will fault or IDA can freeze 
(100% CPU - database corruption).Note that an attacker can drop "baddll" 
on the fly, there are few variants.

Proof of Concept:
A proof of concept code for this vulnerability can be found at  
<http://pb.specialised.info/all/adv/POC/IdaPOC.zip> 
http://pb.specialised.info/all/adv/POC/IdaPOC.zip.


ADDITIONAL INFORMATION

The information has been provided by  <mailto:[email protected]> Piotr 
Bania.
The original article can be found at:  
<http://pb.specialised.info/all/adv/ida-debugger-adv.txt> 
http://pb.specialised.info/all/adv/ida-debugger-adv.txt



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