CVE-2022-24092: Adobe Acrobat DC RCE Vulnerability

CVE-2022-24092 Overview

CVE-2022-24092 is an out-of-bounds write vulnerability affecting Adobe Acrobat Reader DC and related Adobe Acrobat products. This vulnerability allows attackers to achieve arbitrary code execution in the context of the current user by crafting a malicious font file. The attack requires user interaction—specifically, the victim must open a malicious font file embedded within a PDF document or processed by the affected application.

Critical Impact

Successful exploitation allows arbitrary code execution with the privileges of the current user, potentially leading to complete system compromise, data theft, or lateral movement within an enterprise environment.

Affected Products

• Adobe Acrobat DC (Continuous) version 21.007.20099 and earlier
• Adobe Acrobat Reader DC (Continuous) version 21.007.20099 and earlier
• Adobe Acrobat (Classic 2020) version 20.004.30017 and earlier
• Adobe Acrobat Reader (Classic 2020) version 20.004.30017 and earlier
• Adobe Acrobat (Classic 2017) version 17.011.30204 and earlier
• Adobe Acrobat Reader (Classic 2017) version 17.011.30204 and earlier

Discovery Timeline

• 2022-03-18 - CVE-2022-24092 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-24092

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-Bounds Write), a memory corruption flaw that occurs when Adobe Acrobat processes specially crafted font files. The out-of-bounds write condition allows an attacker to corrupt memory beyond the allocated buffer boundaries, potentially overwriting critical data structures or function pointers.

The local attack vector requires the victim to interact with a malicious file, typically delivered through phishing emails containing PDF attachments or drive-by download scenarios. Once the victim opens a PDF document containing the malicious font file, the vulnerable code path is triggered during font parsing and rendering operations.

The vulnerability affects both Windows and macOS platforms, indicating the flaw resides in cross-platform font processing code within the Acrobat engine. The ability to achieve arbitrary code execution makes this vulnerability particularly dangerous for enterprise environments where PDF documents are routinely shared and opened.

Root Cause

The root cause stems from improper bounds checking during font file parsing operations within Adobe Acrobat products. When processing font data structures, the application fails to properly validate the size and boundaries of input data before writing to memory buffers. This allows specially crafted font data to trigger writes beyond the allocated memory region.

Font file formats contain complex data structures including glyph definitions, kerning tables, and metadata. The vulnerability likely exists in the parsing logic for one of these structures, where an attacker-controlled size value or offset can cause the application to write data outside the intended buffer.

Attack Vector

The attack requires user interaction and follows a local attack vector. An attacker typically delivers the malicious payload through:

1. Email-based attacks: A phishing email containing a malicious PDF attachment with embedded font data
2. Web-based delivery: Hosting malicious PDF files on compromised or attacker-controlled websites
3. Document sharing platforms: Uploading malicious PDFs to file sharing services or collaboration platforms

When the victim opens the malicious PDF, Acrobat processes the embedded font file, triggering the out-of-bounds write condition. The attacker can leverage this memory corruption to achieve code execution with the same privileges as the user running Acrobat.

The vulnerability is exploited by crafting a font file with malformed data structures that cause the parser to write beyond allocated buffer boundaries. This can overwrite adjacent memory, potentially including function pointers or security-critical data structures, enabling control flow hijacking.

Detection Methods for CVE-2022-24092

Indicators of Compromise

• Suspicious PDF files containing embedded fonts with anomalous size fields or malformed font table structures
• Acrobat or Acrobat Reader crashes when opening specific PDF documents, particularly those received from untrusted sources
• Unexpected child processes spawned by AcroRd32.exe or Acrobat.exe following PDF file access
• Memory access violation events in Windows Event Log associated with Adobe Acrobat processes

Detection Strategies

• Deploy endpoint detection rules to monitor for Adobe Acrobat processes exhibiting abnormal memory access patterns or unexpected process creation
• Implement email gateway scanning to inspect PDF attachments for malformed font structures before delivery to end users
• Configure application whitelisting to detect and block suspicious executables spawned by Adobe Acrobat processes
• Use YARA rules to identify PDF documents containing suspicious font stream objects with anomalous characteristics

Monitoring Recommendations

• Enable enhanced logging for Adobe Acrobat processes to capture detailed execution telemetry
• Monitor for network connections initiated by Acrobat processes following PDF document access, which may indicate post-exploitation activity
• Implement file integrity monitoring on systems with high-value assets to detect potential exploitation artifacts
• Deploy behavioral analysis solutions capable of detecting memory corruption exploitation techniques

How to Mitigate CVE-2022-24092

Immediate Actions Required

• Update all Adobe Acrobat and Acrobat Reader installations to the latest patched versions immediately
• Enable Protected Mode and Protected View in Adobe Acrobat settings to sandbox PDF rendering
• Implement application control policies to restrict PDF file execution from untrusted locations
• Train users to exercise caution when opening PDF attachments from unknown or suspicious sources

Patch Information

Adobe has released security updates addressing this vulnerability in security bulletin APSB22-01. Organizations should update to the following minimum versions:

• Adobe Acrobat DC (Continuous): Update to version 21.007.20099 or later
• Adobe Acrobat Reader DC (Continuous): Update to version 21.007.20099 or later
• Adobe Acrobat (Classic 2020): Update to version 20.004.30017 or later
• Adobe Acrobat Reader (Classic 2020): Update to version 20.004.30017 or later
• Adobe Acrobat (Classic 2017): Update to version 17.011.30204 or later
• Adobe Acrobat Reader (Classic 2017): Update to version 17.011.30204 or later

Workarounds

• Enable Protected View for all files by navigating to Edit > Preferences > Security (Enhanced) and selecting "Files from potentially unsafe locations"
• Disable JavaScript execution in Acrobat by navigating to Edit > Preferences > JavaScript and unchecking "Enable Acrobat JavaScript"
• Configure email gateways to strip or quarantine PDF attachments pending manual review in high-security environments
• Consider using alternative PDF readers in environments where immediate patching is not feasible

# Windows Registry: Enable Protected View for all PDFs
reg add "HKCU\Software\Adobe\Acrobat Reader\DC\TrustManager" /v bEnhancedSecurityStandalone /t REG_DWORD /d 1 /f
reg add "HKCU\Software\Adobe\Acrobat Reader\DC\TrustManager" /v bEnhancedSecurityInBrowser /t REG_DWORD /d 1 /f