CVE-2017-2939 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat Reader versions 15.020.20042 and earlier, 15.006.30244 and earlier, 11.0.18 and earlier have an exploitable memory corruption vulnerability when processing a malformed cross-reference table. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 10/28/2022
Adobe Acrobat Reader contains a critical memory corruption vulnerability in its handling of malformed cross-reference tables within pdf files. This vulnerability exists in multiple version ranges including 15.020.20042 and earlier, 15.006.30244 and earlier, and 11.0.18 and earlier versions. The flaw occurs when the application processes a specially crafted cross-reference table structure that does not conform to the expected pdf specification, leading to improper memory handling and potential buffer overflow conditions.
The technical implementation of this vulnerability stems from insufficient input validation within the pdf parsing component of Adobe Acrobat Reader. When encountering a malformed cross-reference table, the application fails to properly sanitize or validate the table structure before attempting to process it, resulting in memory corruption. This memory corruption can occur in various memory regions including heap or stack locations, potentially allowing attackers to overwrite critical program data or execution pointers. The vulnerability is classified as a memory safety error and aligns with common weakness enumerations such as CWE-121, which addresses stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios.
From an operational perspective, successful exploitation of this vulnerability enables remote attackers to achieve arbitrary code execution within the context of the user running Adobe Acrobat Reader. This represents a severe privilege escalation risk since the attacker can execute malicious code with the same permissions as the victim user. The attack vector requires the victim to open a maliciously crafted pdf file containing the malformed cross-reference table, making this a typical social engineering target. The vulnerability can be exploited in phishing campaigns or through compromised websites where users might unknowingly download and open malicious documents. This type of attack aligns with tactics described in the attack tree framework where initial access is gained through document delivery and the execution phase occurs within the target application.
The security implications extend beyond simple code execution as this vulnerability can serve as a foothold for more sophisticated attacks. Attackers can leverage this initial compromise to establish persistent access, escalate privileges, or deploy additional malware. The vulnerability's presence in widely used software versions makes it particularly dangerous as it affects a large user base. Organizations should consider implementing additional security controls such as pdf sandboxing, application whitelisting, and user education programs to reduce exposure. The vulnerability also highlights the importance of timely patch management and regular software updates to maintain security posture against known exploits.
Mitigation strategies should include immediate patching of affected Adobe Acrobat Reader versions, implementing network-based security controls such as pdf content filtering, and deploying endpoint protection solutions that can detect and block suspicious pdf file behaviors. Organizations should also consider restricting user permissions when opening pdf files and implementing strict access controls for sensitive documents. The vulnerability demonstrates the critical need for robust input validation and memory safety practices in software development, particularly in applications that process untrusted data formats. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other software components and ensure comprehensive protection against similar memory corruption vulnerabilities.