CVE-2024-41831: Adobe Acrobat RCE Vulnerability

CVE-2024-41831 Overview

CVE-2024-41831 is a Use After Free vulnerability affecting Adobe Acrobat Reader that could result in arbitrary code execution in the context of the current user. This memory corruption flaw allows attackers to potentially execute malicious code when a user opens a specially crafted PDF document. The vulnerability requires user interaction, meaning exploitation depends on social engineering techniques to convince a victim to open a malicious file.

Critical Impact

Successful exploitation enables arbitrary code execution with the privileges of the current user, potentially leading to complete system compromise, data theft, or malware deployment.

Affected Products

• Adobe Acrobat (Classic track) version 20.005.30636 and earlier
• Adobe Acrobat DC (Continuous track) version 24.002.20965 and earlier
• Adobe Acrobat Reader (Classic track) version 24.001.30123 and earlier
• Adobe Acrobat Reader DC (Continuous track) version 24.002.20964 and earlier
• Affected on both Microsoft Windows and Apple macOS platforms

Discovery Timeline

• August 14, 2024 - CVE-2024-41831 published to NVD
• August 15, 2024 - Last updated in NVD database

Technical Details for CVE-2024-41831

Vulnerability Analysis

This Use After Free (CWE-416) vulnerability occurs when Adobe Acrobat Reader improperly handles memory during PDF document processing. Use After Free conditions arise when a program continues to reference memory after it has been freed, leading to corruption of valid data or execution of arbitrary code. In the context of Acrobat Reader, this vulnerability can be triggered when processing maliciously crafted PDF content that manipulates the application's memory management routines.

The vulnerability requires local access and user interaction—specifically, the victim must open a malicious PDF file. Once exploited, the attacker gains the ability to execute code with the same privileges as the current user, potentially allowing full compromise of the affected system including access to sensitive documents, installation of additional malware, or lateral movement within enterprise environments.

Root Cause

The root cause of CVE-2024-41831 lies in improper memory lifecycle management within Adobe Acrobat Reader's PDF parsing and rendering engine. When certain PDF structures or JavaScript operations are processed, memory objects may be freed prematurely while references to those objects still exist. Subsequent operations that attempt to use these dangling references can lead to heap corruption and ultimately arbitrary code execution.

Use After Free vulnerabilities are particularly dangerous in document readers because they process complex, attacker-controlled input formats. PDFs can contain embedded scripts, fonts, images, and interactive elements that exercise numerous code paths, increasing the attack surface for memory corruption issues.

Attack Vector

The attack vector is local, requiring the attacker to deliver a malicious PDF file to the victim through methods such as email attachments, malicious downloads, or compromised websites. Once the victim opens the crafted document in a vulnerable version of Adobe Acrobat Reader, the Use After Free condition is triggered during PDF processing.

The exploitation sequence typically follows this pattern: the attacker crafts a PDF document containing specific structures or JavaScript code designed to trigger premature memory deallocation. When the document is opened, the vulnerable code path is executed, causing the application to reference freed memory. The attacker's payload, strategically placed in the reallocated memory region, is then executed with the privileges of the current user.

Detection Methods for CVE-2024-41831

Indicators of Compromise

• Unexpected Adobe Acrobat Reader crashes or hangs when opening PDF documents
• Unusual process behavior such as Acrobat Reader spawning child processes or making unexpected network connections
• Memory access violations logged in Windows Event Viewer or system crash reports
• Suspicious PDF files with obfuscated JavaScript or unusual embedded objects

Detection Strategies

• Deploy endpoint detection and response (EDR) solutions to monitor Adobe Acrobat Reader process behavior for anomalous memory operations
• Implement email gateway scanning to detect and quarantine potentially malicious PDF attachments
• Monitor for exploitation indicators including abnormal process trees with AcroRd32.exe or Acrobat.exe as parent processes
• Enable Adobe's Protected Mode and Enhanced Security settings to limit exploitation impact

Monitoring Recommendations

• Configure application-level logging for Adobe Acrobat products to capture PDF processing errors
• Monitor for process hollowing or injection attempts originating from Acrobat Reader processes
• Implement file integrity monitoring on systems where Acrobat Reader is installed to detect unauthorized modifications
• Correlate endpoint events with threat intelligence feeds for known PDF-based attack patterns

How to Mitigate CVE-2024-41831

Immediate Actions Required

• Update all Adobe Acrobat and Acrobat Reader installations to the latest patched versions immediately
• Enable Protected View mode in Adobe Acrobat Reader to open untrusted PDFs in a sandboxed environment
• Block or quarantine PDF attachments from untrusted sources at email gateways until patching is complete
• Educate users about the risks of opening PDF documents from unknown or suspicious sources

Patch Information

Adobe has released security updates to address this vulnerability in security bulletin APSB24-57. Organizations should update to the following or later versions:

• Adobe Acrobat DC and Acrobat Reader DC (Continuous track): Update to version 24.002.20991 or later
• Adobe Acrobat 2020 and Acrobat Reader 2020 (Classic track): Update to version 20.005.30655 or later

Enterprise deployments can utilize Adobe Admin Console or third-party patch management solutions to deploy updates at scale.

Workarounds

• Enable Protected View for all files by navigating to Edit → Preferences → Security (Enhanced) and selecting "Files from potentially unsafe locations"
• Disable JavaScript in Acrobat Reader by going to Edit → Preferences → JavaScript and unchecking "Enable Acrobat JavaScript"
• Consider using alternative PDF readers for viewing untrusted documents until patches can be applied
• Implement application whitelisting to prevent unauthorized code execution even if exploitation occurs

# Registry configuration to enable Protected View on Windows (apply via Group Policy)
reg add "HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\DC\TrustManager" /v bEnhancedSecurityInBrowser /t REG_DWORD /d 1 /f
reg add "HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\DC\TrustManager" /v bEnhancedSecurityStandalone /t REG_DWORD /d 1 /f