MS05-021 Microsoft Exchange X-LINK2STATE Heap Overflow PoC

2005-04-20T00:00:00
ID SECURITYVULNS:DOC:8384
Type securityvulns
Reporter Securityvulns
Modified 2005-04-20T00:00:00

Description

Vulnerability Details

The vulnerability is a heap overflow in SvrAppendReceivedChunk function which is located in xlsasink.dll. When transmitting large chunks with X-LINK2STATE verb it is possible to overflow the heap and perform arbitrary memory write in RtlAllocateHeap function. 77fcc663 8901 mov [ecx],eax
77fcc665 894804 mov [eax+0x4],ecx
We are controlling ECX and EAX registers. So rewriting lpTopLevelExceptionFilter can easily get us to our shellcode on the heap.

Regards,

Evgeny Pinchuk