CVE-2018-4976 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader versions 2018.011.20038 and earlier, 2017.011.30079 and earlier, and 2015.006.30417 and earlier have an Out-of-bounds read vulnerability. Successful exploitation could lead to information disclosure.
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Analysis
by VulDB Data Team • 07/21/2024
Adobe Acrobat and Reader applications contain a critical out-of-bounds read vulnerability that affects multiple versions across different release cycles. This vulnerability stems from improper input validation within the software's document processing engine, specifically when handling malformed PDF files. The flaw manifests as an insufficient bounds checking mechanism that allows an attacker to craft malicious PDF documents which, when opened by vulnerable versions of Adobe Reader or Acrobat, trigger memory access violations. The vulnerability is classified as CWE-129, representing an insufficient bounds checking issue that can lead to unauthorized data access. When exploited, this vulnerability enables an attacker to read memory locations beyond the intended buffer boundaries, potentially exposing sensitive information stored in adjacent memory regions. The technical implementation involves the software's failure to properly validate array indices or buffer limits during PDF parsing operations, creating a scenario where crafted input can bypass normal memory access controls.
The operational impact of CVE-2018-4976 extends beyond simple information disclosure, as it can serve as a precursor to more severe exploitation techniques within the broader ATT&CK framework. Attackers can leverage this vulnerability to extract memory contents including encryption keys, user credentials, or other sensitive data that may be stored in adjacent memory locations. The vulnerability's exploitation requires a user to open a maliciously crafted PDF file, making it particularly dangerous in phishing campaigns or targeted attacks where social engineering plays a crucial role. The affected versions span multiple years of Adobe's release cycle, indicating a persistent flaw in the software's input validation mechanisms that was not adequately addressed in the affected release branches. This vulnerability demonstrates the importance of proper bounds checking in security-critical applications and aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as attackers may use information disclosure to gather intelligence for subsequent exploitation phases.
Organizations should implement immediate mitigation strategies to protect against exploitation of this vulnerability, including prompt patching of all affected Adobe Reader and Acrobat installations. The recommended remediation approach involves updating to the latest available versions that contain fixes for this specific out-of-bounds read condition. Security administrators should also consider implementing additional protective measures such as PDF file scanning, restricted browsing environments, and user education regarding suspicious document attachments. The vulnerability's presence across multiple release cycles highlights the need for comprehensive vulnerability management programs that address not only current patches but also legacy software versions that may continue to pose risks. Organizations should also monitor for related exploitation attempts and implement network-based detection mechanisms to identify potential exploitation attempts targeting this specific vulnerability. Proper input validation and bounds checking measures should be enforced throughout the application's document processing pipeline to prevent similar issues from occurring in future releases, aligning with security best practices established in industry standards and security frameworks.