CVE-2019-7761 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader versions 2019.010.20100 and earlier, 2019.010.20099 and earlier, 2017.011.30140 and earlier, 2017.011.30138 and earlier, 2015.006.30495 and earlier, and 2015.006.30493 and earlier have a use after free vulnerability. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 06/17/2024
Adobe Acrobat and Reader applications contain a use after free vulnerability that affects multiple versions across different release cycles. This critical flaw exists within the software's memory management mechanisms where a freed memory block is still referenced or accessed by subsequent operations. The vulnerability manifests when the application processes certain PDF files that trigger improper memory deallocation followed by subsequent access to the same memory region. This particular use after free condition represents a fundamental breakdown in the application's memory safety protocols and creates an exploitable entry point for malicious actors. The vulnerability has been classified under the Common Weakness Enumeration (CWE) category CWE-416 which specifically addresses the use of freed memory conditions in software applications.
The technical exploitation of this vulnerability requires an attacker to craft a malicious PDF file that, when opened by the vulnerable Adobe application, triggers the specific memory management error. During normal operation, the application allocates memory for processing PDF elements such as embedded objects, JavaScript code, or complex graphics. When these elements are processed in a particular sequence, the application frees memory blocks associated with certain objects while simultaneously maintaining references to those same memory regions. This creates a scenario where subsequent operations can access memory that has already been deallocated, allowing for potential code execution. The exploitability of this condition is enhanced by the fact that PDF files can be easily distributed through email attachments, web downloads, or malicious websites, making it a particularly dangerous vulnerability in enterprise environments where Adobe Reader is commonly used for document review.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise. Successful exploitation allows attackers to execute arbitrary code with the privileges of the user running the vulnerable Adobe application, typically resulting in full system control. This vulnerability poses significant risks to organizations as it can be leveraged for data exfiltration, persistence mechanisms, privilege escalation, and lateral movement within networks. The vulnerability affects a wide range of Adobe Reader versions, spanning multiple years of releases, indicating that this memory management flaw has persisted across different development cycles. The widespread nature of Adobe Reader installations across enterprise environments amplifies the potential damage, as a single compromised system can serve as a foothold for broader attacks. Security researchers have identified this vulnerability as particularly concerning due to its potential for remote code execution without user interaction, making it a prime target for automated exploit delivery mechanisms.
Organizations should immediately apply the vendor-provided security patches released by Adobe to address this vulnerability. The recommended mitigation strategy involves updating all affected Adobe Acrobat and Reader installations to versions that contain memory management fixes for the use after free condition. System administrators should prioritize patch deployment across all endpoints, particularly those with high-value data access or privileged user accounts. Additional protective measures include implementing PDF file filtering at network perimeters, restricting Adobe Reader functionality through security policies, and monitoring for suspicious PDF file access patterns. The vulnerability aligns with ATT&CK technique T1059 which covers command and scripting interpreter usage, as exploitation typically involves executing malicious code through compromised Adobe applications. Network segmentation and endpoint protection solutions can provide additional defense layers against exploitation attempts, though the most effective protection remains timely patch management and user awareness training to avoid opening suspicious PDF attachments.