CVE-2024-11612: 7-Zip CopyCoder Infinite Loop DoS Flaw

CVE-2024-11612 Overview

CVE-2024-11612 is an Infinite Loop Denial-of-Service vulnerability affecting 7-Zip's CopyCoder stream processing functionality. This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of 7-Zip. While interaction with the 7-Zip library is required to exploit this vulnerability, attack vectors may vary depending on the implementation.

The specific flaw exists within the processing of streams, where a logic error can lead to an infinite loop. An attacker can leverage this vulnerability to create a denial-of-service condition on the system, causing affected applications to become unresponsive. This vulnerability was tracked as ZDI-CAN-24307.

Critical Impact
Remote attackers can trigger an infinite loop in 7-Zip's stream processing, causing applications using the library to hang indefinitely and become unresponsive, potentially affecting system availability.

Affected Products

7-Zip (all versions prior to patched release)
Applications and services utilizing the 7-Zip library for archive processing
Systems with 7-Zip integrated for automated archive handling

Discovery Timeline

2024-11-22 - CVE-2024-11612 published to NVD
2025-08-07 - Last updated in NVD database

Technical Details for CVE-2024-11612

Vulnerability Analysis

This vulnerability resides in the CopyCoder component of 7-Zip, specifically within the stream processing logic. The flaw is classified under CWE-835 (Loop with Unreachable Exit Condition), indicating that the code contains a loop that lacks proper termination conditions under certain input scenarios.

When processing specially crafted archive streams, the CopyCoder function enters an infinite loop state due to a logic error in stream handling. This causes the affected process to consume CPU resources indefinitely without completing the operation. The vulnerability requires user interaction in the sense that a victim must process a malicious archive, but this can occur through various attack vectors including email attachments, web downloads, or automated archive processing systems.

The network-accessible nature of this vulnerability means that attackers can deliver malicious payloads remotely, though exploitation requires the target to interact with the crafted content. The impact is limited to availability, with no direct effect on data confidentiality or integrity.

Root Cause

The root cause of CVE-2024-11612 is a logic error in 7-Zip's CopyCoder stream processing implementation. The code fails to properly validate or handle certain stream conditions, resulting in an infinite loop scenario (CWE-835). This occurs when the stream processing logic encounters specific malformed or crafted input that causes the loop exit conditions to never be satisfied.

The CopyCoder component is responsible for copying data between streams during archive operations. When processing certain stream configurations, the logic fails to advance properly or incorrectly evaluates termination conditions, causing the processing loop to continue indefinitely.

Attack Vector

The attack vector for CVE-2024-11612 involves delivering a maliciously crafted archive file to a victim who uses 7-Zip or an application that integrates the 7-Zip library. Attack scenarios include:

The vulnerability can be exploited through various delivery mechanisms. An attacker could send a specially crafted archive via email, host it on a malicious website for download, or upload it to file sharing services. When the victim attempts to open, extract, or preview the archive using 7-Zip, the infinite loop is triggered.

Automated systems that process archives are particularly at risk, as they may automatically handle incoming archives without user verification. This includes backup systems, email gateways with archive scanning, and web applications that accept archive uploads.

For technical details on the vulnerability, refer to the Zero Day Initiative Advisory ZDI-24-1606.

Detection Methods for CVE-2024-11612

Indicators of Compromise

7-Zip processes (7z.exe, 7zFM.exe, 7zG.exe) consuming 100% CPU for extended periods
Applications using 7-Zip library becoming unresponsive when processing archive files
System logs showing hung or unresponsive archive processing operations
Unusual archive files with suspicious stream configurations

Detection Strategies

Monitor for 7-Zip processes that exceed normal execution time thresholds during archive operations
Implement endpoint detection rules for processes entering infinite loop states with high CPU consumption
Deploy network monitoring to identify downloads of archive files from suspicious sources
Use SentinelOne's behavioral AI to detect anomalous process behavior indicative of denial-of-service conditions

Monitoring Recommendations

Configure process monitoring to alert on 7-Zip processes exceeding CPU usage thresholds for extended durations
Implement application timeout mechanisms for automated archive processing systems
Monitor system resource utilization for unexpected spikes in CPU consumption
Enable logging for archive processing operations to identify problematic files

How to Mitigate CVE-2024-11612

Immediate Actions Required

Update 7-Zip to the latest patched version as soon as a fix is available
Implement process timeout controls for applications that use 7-Zip library
Exercise caution when opening archives from untrusted sources
Consider temporary restrictions on automated archive processing from external sources

Patch Information

Organizations should monitor the official 7-Zip website and the Zero Day Initiative Advisory ZDI-24-1606 for patch availability and update information. Apply vendor patches promptly once released. Ensure all systems using 7-Zip, including those with embedded library usage, are updated.

Workarounds

Implement process timeouts for 7-Zip operations to prevent indefinite hangs
Restrict archive processing to trusted sources only until patch is applied
Use alternative archive utilities for processing untrusted files temporarily
Deploy application control policies to monitor and limit 7-Zip execution contexts

bash

# Example: Set process timeout for archive operations on Linux
timeout 300 7z x suspicious_archive.7z

# Example: Windows PowerShell with timeout
Start-Process -FilePath "7z.exe" -ArgumentList "x", "archive.7z" -Wait -Timeout 300