CVE-2022-27786 in Acrobat Reader
Summary
by MITRE • 05/11/2022
Acrobat Reader DC versions 22.001.20085 (and earlier), 20.005.3031x (and earlier) and 17.012.30205 (and earlier) are affected by a use-after-free vulnerability in the processing of fonts that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.
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Analysis
by VulDB Data Team • 05/14/2022
This vulnerability represents a critical use-after-free flaw in Adobe Acrobat Reader DC affecting multiple version lines including 22.001.20085 and earlier, 20.005.3031x and earlier, and 17.012.30205 and earlier. The vulnerability specifically manifests during font processing operations within the PDF rendering engine, creating a scenario where freed memory locations can be accessed and potentially overwritten by malicious code. From a cybersecurity perspective, this represents a classic heap-based memory corruption vulnerability that can be exploited to achieve arbitrary code execution. The flaw falls under CWE-416 which categorizes use-after-free conditions as a fundamental memory safety issue where program memory is accessed after it has been freed, creating opportunities for attackers to manipulate program execution flow. The vulnerability requires user interaction for exploitation, meaning a victim must open a maliciously crafted PDF file containing specially constructed font data that triggers the memory corruption during parsing operations.
The operational impact of this vulnerability extends beyond simple code execution to potentially enable full system compromise when users open malicious documents. Attackers can leverage this flaw to execute malicious payloads directly within the context of the current user, bypassing many traditional security controls that operate at higher privilege levels. This makes the vulnerability particularly dangerous in enterprise environments where users frequently open PDF documents from various sources including email attachments, web downloads, and shared network drives. The exploitation process typically involves crafting a PDF file with malformed font structures that cause the Acrobat Reader application to free memory associated with font processing while simultaneously attempting to access that same memory location. This creates a race condition where attackers can inject their own code into the freed memory space, effectively hijacking the application's execution flow. The vulnerability's presence in multiple version lines indicates a persistent flaw in Adobe's font handling code that was not adequately addressed across their product lifecycle.
Security professionals should implement immediate mitigations including prompt patch deployment for all affected Acrobat Reader versions, user education about avoiding untrusted PDF documents, and network-based filtering of suspicious PDF content. Organizations should consider implementing application whitelisting controls that restrict execution of Acrobat Reader to trusted environments only, while also monitoring for unusual PDF processing activity that might indicate exploitation attempts. The vulnerability aligns with attack patterns documented in the MITRE ATT&CK framework under techniques such as T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter) where adversaries leverage application vulnerabilities to execute malicious code. Additionally, this vulnerability demonstrates the importance of secure coding practices and memory management in document processing applications, as font handling represents a common attack surface in office productivity software. Network administrators should also consider implementing sandboxing solutions for PDF processing and monitoring for indicators of compromise related to Acrobat Reader memory corruption attempts, particularly in environments where users frequently interact with external PDF content. The remediation process requires careful coordination between IT teams and end users to ensure complete patch coverage across all affected systems while maintaining business continuity during the remediation period.