Kaspersky Antivirus - ZIP File Format Use-After-Free Vulnerability

ID EDB-ID:38736
Type exploitdb
Reporter Google Security Research
Modified 2015-11-16T00:00:00


Kaspersky Antivirus - ZIP File Format Use-After-Free Vulnerability. Dos exploit for windows platform

                                            Source: https://code.google.com/p/google-security-research/issues/detail?id=521

Fuzzing the ZIP file format found multiple memory corruption issues, some of which are obviously exploitable for remote code execution as NT AUTHORITY\SYSTEM on any system with Kaspersky Antivirus.

This testcase should fault by jumping to an unmapped address

(aac.fa4): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
eax=cccccccc ebx=00000000 ecx=01bc2974 edx=73a10002 esi=02e0a598 edi=5b2266bb
eip=cccccccc esp=05dde330 ebp=05dde354 iopl=0         nv up ei pl nz na po nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00010202
cccccccc ??              ???

# where did that come from?

0:036> kvn 2
 # ChildEBP RetAddr  Args to Child              
00 05dde32c 739fd847 02e0a598 05dde370 00000000 0xcccccccc
01 05dde354 739fe438 01bc2974 002266bb 05dde370 prcore!PragueUnload+0x2687

0:036> ub 739fd847 L9
739fd833 8b4d08          mov     ecx,dword ptr [ebp+8]
739fd836 8b7104          mov     esi,dword ptr [ecx+4]
739fd839 8975ec          mov     dword ptr [ebp-14h],esi
739fd83c 85f6            test    esi,esi
739fd83e 740a            je      prcore!PragueUnload+0x268a (739fd84a)
739fd840 8b16            mov     edx,dword ptr [esi]
739fd842 8b02            mov     eax,dword ptr [edx]
739fd844 56              push    esi
739fd845 ffd0            call    eax

# that pointer is in edx

0:088> dd edx
739a0002  cccccccc cccccccc cccccccc 8b55cccc
739a0012  77e95dec ccffffff cccccccc 8b55cccc
739a0022  0c4d8bec 8b04418b 42390855 501a7504
739a0032  0a8b018b d3e85150 83fffff9 c0850cc4
739a0042  01b80775 5d000000 5dc033c3 8b55ccc3
739a0052  0c4d8bec 8b04418b 42390855 501a7504
739a0062  0a8b018b 63e85150 83fffff9 c0850cc4
739a0072  01b80775 5d000000 5dc033c3 6c83ccc3

# So what is that?

0:088> !address edx
Usage:                  Image
Base Address:           73971000
End Address:            739aa000
Region Size:            00039000
State:                  00001000	MEM_COMMIT
Protect:                00000020	PAGE_EXECUTE_READ
Type:                   01000000	MEM_IMAGE
Allocation Base:        73970000
Allocation Protect:     00000080	PAGE_EXECUTE_WRITECOPY
Image Path:             C:\Program Files (x86)\Kaspersky Lab\Kaspersky Internet Security 15.0.2\prcore.dll
Module Name:            prcore
Loaded Image Name:      C:\Program Files (x86)\Kaspersky Lab\Kaspersky Internet Security 15.0.2\prcore.dll
Mapped Image Name:      
0:088> !chkimg prcore
0 errors : prcore 

# Hmm, so why is esi pointing there?

0:088> !address esi
Mapping file section regions...
Mapping module regions...
Mapping PEB regions...
Mapping TEB and stack regions...
Mapping heap regions...
Mapping page heap regions...
Mapping other regions...
Mapping stack trace database regions...
Mapping activation context regions...

Usage:                  Heap
Base Address:           02a00000
End Address:            02c33000
Region Size:            00233000
State:                  00001000	MEM_COMMIT
Protect:                00000004	PAGE_READWRITE
Type:                   00020000	MEM_PRIVATE
Allocation Base:        02a00000
Allocation Protect:     00000004	PAGE_READWRITE
More info:              heap owning the address: !heap 0x4a0000
More info:              heap segment
More info:              heap entry containing the address: !heap -x 0x2bf4760

0:088> !heap -x 0x2bf4760
Entry     User      Heap      Segment       Size  PrevSize  Unused    Flags
02bf4758  02bf4760  004a0000  02b00ac8        60      -            0  LFH;free 

# So looks like an exploitable use after free vulnerability.

Proof of Concept: