CVE-2023-34153: ImageMagick RCE Vulnerability

CVE-2023-34153 Overview

A critical shell command injection vulnerability has been identified in ImageMagick, a widely-used open-source software suite for image manipulation. This security flaw allows attackers to inject and execute arbitrary shell commands through the video:vsync or video:pixel-format options during VIDEO encoding/decoding operations. The vulnerability arises from improper sanitization of user-supplied input when these video processing options are passed to underlying system commands.

Critical Impact

Successful exploitation of this vulnerability enables attackers to execute arbitrary shell commands on the target system, potentially leading to complete system compromise, data theft, or lateral movement within a network.

Affected Products

• ImageMagick (all versions prior to fix)
• Fedora Project Extra Packages for Enterprise Linux 8.0
• Fedora 37 and 38
• Red Hat Enterprise Linux 6.0 and 7.0

Discovery Timeline

• 2023-05-30 - CVE-2023-34153 published to NVD
• 2025-01-10 - Last updated in NVD database

Technical Details for CVE-2023-34153

Vulnerability Analysis

CVE-2023-34153 is a command injection vulnerability (CWE-77) that exists within ImageMagick's video processing functionality. When users specify video encoding or decoding options such as video:vsync or video:pixel-format, the application fails to properly sanitize these values before passing them to the underlying shell for execution. This creates an opportunity for attackers to inject malicious commands that will be executed with the privileges of the ImageMagick process.

The vulnerability is particularly dangerous in environments where ImageMagick processes user-uploaded content, such as web applications that resize or convert images. An attacker could craft a malicious input file or command-line arguments that include shell metacharacters, allowing arbitrary command execution on the server.

Root Cause

The root cause of this vulnerability stems from insufficient input validation and sanitization in ImageMagick's video processing pipeline. When video-related options are specified, the application constructs shell commands using these option values without properly escaping or validating them. This allows shell metacharacters (such as semicolons, backticks, or pipe characters) to break out of the intended command context and execute arbitrary commands.

The flaw specifically affects the VIDEO coder module, which interfaces with external video processing tools. The option values are concatenated into command strings without proper quoting or escaping, creating a classic command injection scenario.

Attack Vector

This vulnerability requires local access to exploit, where an attacker must be able to either provide command-line arguments to ImageMagick or supply a specially crafted input file that triggers the vulnerable code path. The attack requires user interaction, as the victim must process the malicious input using ImageMagick with video encoding/decoding options enabled.

An attacker could exploit this vulnerability by:

1. Crafting a malicious input that includes shell metacharacters in video-related options
2. Supplying this input to an ImageMagick process (directly via CLI or through an application that uses ImageMagick)
3. When ImageMagick processes the video options, the injected commands execute with the privileges of the ImageMagick process

The vulnerability is exploited through specially crafted values in the video:vsync or video:pixel-format parameters that contain shell command sequences. For detailed technical information, see the GitHub ImageMagick Issue #6338.

Detection Methods for CVE-2023-34153

Indicators of Compromise

• Unusual process spawning from ImageMagick processes (e.g., convert, magick, mogrify) executing unexpected child processes
• Command-line arguments containing shell metacharacters such as ;, |, `, $(), or && in video processing options
• Unexpected network connections originating from ImageMagick processes
• Log entries showing malformed or suspicious video encoding/decoding parameters

Detection Strategies

• Implement process monitoring to detect child processes spawned by ImageMagick binaries that deviate from expected behavior
• Configure application-level logging to capture all ImageMagick command-line invocations and inspect for injection patterns
• Deploy endpoint detection rules that alert on ImageMagick processes executing shell commands or spawning interpreter processes (/bin/sh, /bin/bash, cmd.exe)
• Use file integrity monitoring on systems running ImageMagick to detect unauthorized modifications

Monitoring Recommendations

• Enable verbose logging for all ImageMagick operations in web applications and monitor for anomalous video processing requests
• Implement network segmentation to limit the potential impact if ImageMagick processes are compromised
• Monitor system call activity from ImageMagick processes using tools like auditd or similar endpoint telemetry
• Review application logs for patterns indicating attempted command injection in media processing workflows

How to Mitigate CVE-2023-34153

Immediate Actions Required

• Update ImageMagick to the latest patched version immediately
• If immediate patching is not possible, disable video encoding/decoding functionality by modifying the ImageMagick policy configuration
• Audit all systems running ImageMagick and identify which applications rely on video processing capabilities
• Review and restrict the ImageMagick security policy to limit the delegates and coders that can be invoked

Patch Information

Patches and updates are available through vendor channels. System administrators should consult the following resources for patch information:

• Red Hat CVE-2023-34153 - Red Hat security advisory with patch details
• Red Hat Bug Report #2210660 - Red Hat Bugzilla tracking entry
• Fedora Package Announcement - Fedora update notification
• GitHub ImageMagick Issue #6338 - Upstream issue tracker

Workarounds

• Disable the VIDEO coder entirely by adding a policy directive to deny video processing operations
• Implement strict input validation at the application layer before passing any user-supplied data to ImageMagick
• Run ImageMagick processes in a sandboxed environment with restricted privileges and limited system access
• Use ImageMagick's built-in policy mechanism to disable potentially dangerous delegates and coders

# ImageMagick policy.xml configuration to mitigate CVE-2023-34153
# Add to /etc/ImageMagick-*/policy.xml or similar location

# Disable VIDEO coder to prevent exploitation
<policy domain="coder" rights="none" pattern="VIDEO" />

# Alternatively, disable all delegates that may invoke external commands
<policy domain="delegate" rights="none" pattern="*" />

# Restrict resource usage for defense in depth
<policy domain="resource" name="temporary-path" value="/tmp/imagemagick" />
<policy domain="resource" name="memory" value="256MiB" />
<policy domain="resource" name="disk" value="1GiB" />