Music Animation Machine MIDI Player Local Crash Explained

What this paper is

This paper is a Proof-of-Concept (PoC) exploit that demonstrates a local crash vulnerability in the Music Animation Machine (MAM) MIDI Player, specifically version Release 035. The vulnerability is triggered by opening a specially crafted, malformed MIDI file. The exploit is written in Python and generates this malicious file.

Simple technical breakdown

The MAM MIDI Player application is designed to process MIDI files. MIDI files have a specific structure. This exploit creates a "malformed" MIDI file by writing a very large, repetitive string of bytes into a file named "test.mid". When the MAM MIDI Player attempts to read and process this excessively large and malformed data, it likely attempts to allocate a buffer or perform an operation that fails due to the unexpected input size and structure, leading to a program crash (Denial of Service - DoS).

Complete code and payload walkthrough

The provided Python script is straightforward. Let's break it down:

#!/usr/bin/python

buffer     = "\x31\x33\x33\x37" * 1337

try:
    f = open("test.mid",'w')
    f.write(buffer)
    f.close()

    print " Vulnerable file created!..."
    print " Open the mid file with the application and Voila!! , it crashes!!\n"
except:
    print "[-] Error occured!"

Code Fragment/Block -> Practical Purpose:

• #!/usr/bin/python: This is a shebang line, indicating that the script should be executed using the Python interpreter.
• buffer = "\x31\x33\x33\x37" * 1337:
  • "\x31\x33\x33\x37": This is a sequence of hexadecimal bytes. In ASCII, \x31 is '1', \x33 is '3', and \x37 is '7'. So, this sequence represents the string "1337". The use of "1337" is a common hacker slang.
  • * 1337: This operator repeats the preceding string (the "1337" sequence) 1337 times. This creates a very large string of repeating "1337" bytes. The exact value 1337 is likely chosen to be large enough to trigger the vulnerability but not so large as to cause immediate system resource exhaustion before the application attempts to process it.
  • Practical Purpose: To construct the malicious payload data that will be written into the MIDI file. This data is intentionally malformed and excessively large.
• try:: This initiates a try block, which is used for error handling. The code within this block will be executed, and if any exceptions (errors) occur, they will be caught by the except block.
• f = open("test.mid",'w'):
  • open("test.mid", 'w'): This function opens a file named "test.mid" in write mode ('w'). If the file exists, its contents will be erased. If it doesn't exist, it will be created.
  • f = ...: The opened file object is assigned to the variable f.
  • Practical Purpose: To prepare a file named "test.mid" for writing the malicious data.
• f.write(buffer):
  • f.write(buffer): This writes the contents of the buffer variable (the large string of "1337" bytes) into the opened file "test.mid".
  • Practical Purpose: To populate the "test.mid" file with the malformed data that will cause the crash.
• f.close():
  • f.close(): This closes the file "test.mid", ensuring that all data is written and system resources are released.
  • Practical Purpose: To finalize the creation of the malicious file.
• print " Vulnerable file created!...": This line prints a success message to the console indicating that the file has been created.
• print " Open the mid file with the application and Voila!! , it crashes!!\n": This line provides instructions to the user on how to trigger the crash.
• except:: This block catches any exceptions that occurred within the try block.
• print "[-] Error occured!": If an error occurred during file operations (e.g., insufficient permissions to write the file), this error message will be printed.

Shellcode/Payload Segment Explanation:

There is no explicit shellcode or complex multi-stage payload in this PoC. The "payload" is simply the malformed data written into the test.mid file. The bytes \x31\x33\x33\x37 repeated many times are the core of the exploit's data. The goal is not to execute arbitrary code but to cause the application to crash by overwhelming its input processing logic.

Practical details for offensive operations teams

• Required Access Level: Local user access to the target machine is required to create the test.mid file and then manually open it with the vulnerable application. No elevated privileges are needed for file creation.
• Lab Preconditions:
  • A lab environment with the vulnerable version of MAM Player (Release 035) installed on a Windows XP SP2 English operating system. A virtual machine (like VirtualBox, as mentioned in the paper) is ideal for this.
  • Python interpreter installed on the machine where the exploit script will be run.
• Tooling Assumptions:
  • Python 2.x (as the script uses print as a statement, common in Python 2).
  • A text editor or IDE to save and run the Python script.
  • The MAM MIDI Player application itself.
• Execution Pitfalls:
  • Incorrect Software Version: The exploit is specific to Release 035. Older or newer versions might not be vulnerable.
  • File Path Issues: If the script is run from a directory where the user doesn't have write permissions, the open() call will fail.
  • Antivirus/EDR: While this is a simple DoS, very aggressive endpoint security solutions might flag the creation of a file with unusual content or the subsequent attempt to open it if they have signatures for known crash-inducing patterns. However, for a simple DoS, this is less likely than for code execution exploits.
  • Manual Triggering: The exploit requires the operator (or a user on the target system) to manually open the test.mid file with the MAM Player. This is a significant limitation for remote exploitation.
  • Buffer Size: The exact size of the buffer (1337 * 4 bytes) is crucial. If it's too small, it might not trigger the crash. If it's excessively large, it might cause system instability before the application can crash. The value 1337 is a common choice in exploit development for its symbolic meaning and to ensure sufficient size.
• Telemetry:
  • File Creation: The creation of test.mid in the directory where the script is executed.
  • Application Crash: The MAM MIDI Player process will terminate unexpectedly. This might be visible as the application window disappearing, or an "Application has stopped working" dialog box appearing on Windows.
  • Event Logs: Windows Event Viewer might log an application crash event (Application Error).

Where this was used and when

• Context: This exploit targets a specific, older desktop application (Music Animation Machine MIDI Player). Its primary use case would be for demonstrating a Denial of Service vulnerability in that particular software.
• When: Published on January 3, 2011. The vulnerability likely existed in the software prior to this date. Such exploits are typically discovered and published when the software is in active use or shortly after its development cycle. Given the age of Windows XP and the application's release date (implied by the filename MAMPlayer2006aug19_035.zip), this vulnerability would have been relevant around the mid-to-late 2000s and early 2010s.

Defensive lessons for modern teams

• Input Validation: Applications must rigorously validate all input, especially data from external sources like files. This includes checking file formats, sizes, and content for expected patterns. Unexpected or excessively large data should be handled gracefully, not by crashing.
• Secure Coding Practices: Developers should be trained in secure coding practices to avoid common vulnerabilities like buffer overflows or improper handling of large data structures.
• Fuzzing: Regularly fuzzing applications with malformed inputs is a critical technique for discovering such vulnerabilities before they are exploited in the wild.
• Software Updates: Keeping software updated is paramount. Vendors often release patches to fix known vulnerabilities. In this case, updating to a newer version of the MAM Player (if available and supported) or using a different MIDI player would mitigate this specific risk.
• Least Privilege: Running applications with the least privilege necessary can limit the impact of a crash. While this exploit is a DoS, in other scenarios, a crash could be a precursor to code execution.

ASCII visual (if applicable)

This exploit is a simple file-based DoS. An ASCII visual is not particularly applicable as there's no complex network interaction or multi-component architecture to depict. The flow is linear:

+-----------------+     +-----------------+     +-----------------+
| Python Script   | --> | Create test.mid | --> | MAM MIDI Player |
| (Generates data)|     | (Malformed data)|     | (Opens test.mid)|
+-----------------+     +-----------------+     +-------+---------+
                                                        |
                                                        | (Input Processing)
                                                        v
                                                 +--------------+
                                                 | Application  |
                                                 | Crash (DoS)  |
                                                 +--------------+

Source references

• Paper ID: 15897
• Paper Title: Music Animation Machine MIDI Player Local Crash (PoC)
• Author: c0d3R'Z
• Published: 2011-01-03
• Software Link: http://www.musanim.com/player/MAMPlayer2006aug19_035.zip
• Version: Release 035
• Tested on: Windows XP SP2 EN (VirtualBox)
• Exploit-DB URL: https://www.exploit-db.com/papers/15897

Original Exploit-DB Content (Verbatim)

# Exploit Title: Music Animation Machine MIDI Player Local Crash PoC
# Date: 1/3/2011
# Author: c0d3R'Z
# Software Link: http://www.musanim.com/player/MAMPlayer2006aug19_035.zip
# Version: Release 035
# Tested on: Windows XP SP2 EN (VirtualBox)

 
# The application crashes when trys to convert a malformed midi file
 
#!/usr/bin/python
 
buffer     = "\x31\x33\x33\x37" * 1337
 
try:
    f = open("test.mid",'w')
    f.write(buffer)
    f.close()
 
    print " Vulnerable file created!..."
    print " Open the mid file with the application and Voila!! , it crashes!!\n"
except:
    print "[-] Error occured!"