CVE-2025-61043

Executive Summary

CVE-2025-61043 is an out-of-bounds read vulnerability discovered in Monkey's Audio version 11.31. The flaw resides in the CAPECharacterHelper::GetUTF16FromUTF8 function, which improperly handles the length of an input UTF-8 string, causing the function to read past the allocated memory boundary. This can lead to a crash or the exposure of sensitive data. The vulnerability has a CVSS score of 0.0, indicating that no official CVSS vector has been assigned, but the technical impact is clear. No public exploit code or patch is currently available.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects a standalone audio application, Monkey's Audio.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which typically indicates that a CVSS vector has not been calculated or published. However, based on the description, the vulnerability is an out-of-bounds read (CWE-125). The threat level is considered Medium due to the potential for information disclosure and denial of service. The attack vector is likely local or network-based, depending on how the application processes input.

Deep Dive & Mechanics

The vulnerability is an out-of-bounds read in the CAPECharacterHelper::GetUTF16FromUTF8 function. This function is responsible for converting a UTF-8 encoded string to UTF-16. The issue arises when the function is provided with a UTF-8 string whose length is not properly validated. Specifically, the function may read beyond the allocated buffer when processing the input string, leading to a read of adjacent memory.

Technical Details:

• Function: CAPECharacterHelper::GetUTF16FromUTF8
• Root Cause: Improper length validation of the input UTF-8 string.
• Impact: The function reads past the memory boundary, potentially causing a crash (denial of service) or leaking sensitive data from memory.
• Attack Vector: An attacker could craft a malicious audio file or input that triggers this function with a malformed UTF-8 string, leading to the out-of-bounds read.

Vulnerable vs. Patched Code

No patched version is available. The vulnerable code is in Monkey's Audio 11.31. The following is a hypothetical example of the vulnerable code and a potential fix.

Vulnerable Code (Hypothetical):

void CAPECharacterHelper::GetUTF16FromUTF8(const char* utf8, size_t utf8Len, wchar_t* utf16, size_t& utf16Len) {
    // No check for utf8Len being too large
    for (size_t i = 0; i < utf8Len; ++i) {
        // Read from utf8[i] without bounds check
        // ...
    }
}

Patched Code (Hypothetical):

void CAPECharacterHelper::GetUTF16FromUTF8(const char* utf8, size_t utf8Len, wchar_t* utf16, size_t& utf16Len) {
    // Add bounds check
    if (utf8Len > MAX_UTF8_LENGTH) {
        // Handle error
        return;
    }
    for (size_t i = 0; i < utf8Len; ++i) {
        // Safe read
        // ...
    }
}

Exploitation & Lab Setup

Red Team

To exploit this vulnerability, an attacker would need to craft a malicious input that triggers the out-of-bounds read. Since no public exploit code is available, the following is a conceptual approach:

1. Craft a Malicious File: Create a file that contains a UTF-8 string with an invalid length field that causes the function to read beyond the buffer.
2. Deliver the File: Use social engineering or other methods to get the target to open the file with Monkey's Audio.
3. Trigger the Vulnerability: When the application processes the file, the out-of-bounds read occurs, potentially leaking sensitive data or causing a crash.

Lab Setup:

• Target: Windows or Linux system with Monkey's Audio 11.31 installed.
• Tools: A debugger (e.g., WinDbg, GDB) to observe the crash and memory read.
• Payload: A crafted audio file with a malformed UTF-8 string.

Blue Team

To detect exploitation attempts:

• Monitor for crashes of Monkey's Audio.
• Use memory analysis tools to detect out-of-bounds reads.
• Implement input validation for any files processed by the application.

Indicators of Compromise (IOCs)

• File Hashes: (No specific hashes available)
• Process Behavior: Monkey's Audio process (MAC.exe or similar) crashes unexpectedly.
• Memory Patterns: Reads from memory addresses outside the allocated buffer.
• Network Traffic: (Unlikely, as this is a local vulnerability)

Detection Engineering

YARA Rule

rule CVE_2025_61043_Monkeys_Audio_OOB_Read {
    meta:
        description = "Detects potential exploitation of CVE-2025-61043 in Monkey's Audio"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "CVE-2025-61043"
    strings:
        $s1 = "CAPECharacterHelper::GetUTF16FromUTF8" ascii wide nocase
        $s2 = "Monkey's Audio" ascii wide nocase
    condition:
        $s1 or $s2
}

Sigma Rule

title: CVE-2025-61043 Monkey's Audio Out-of-Bounds Read
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects crashes or memory access violations related to CVE-2025-61043
author: Valters IT
date: 2025-01-01
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\MAC.exe'
        CommandLine|contains: '*.ape'
    condition: selection
falsepositives:
    - Legitimate use of Monkey's Audio
level: medium

Suricata Rule

alert tcp any any -> any any (msg:"CVE-2025-61043 Monkey's Audio Out-of-Bounds Read"; flow:to_server; content:"Monkey's Audio"; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

• Patch: No patch is currently available. Monitor the vendor's website for updates.
• Mitigation: Avoid opening untrusted audio files with Monkey's Audio 11.31. Use alternative audio players until a patch is released.
• Workaround: If possible, disable the processing of UTF-8 strings in the application or apply input validation at the application level.

Valters IT Signature: This report is prepared by Valters IT, an elite DevSecOps and Cyber Threat Intelligence team. For further inquiries, contact us at [valters@example.com].