CVE-2018-12784 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader 2018.011.20040 and earlier, 2017.011.30080 and earlier, and 2015.006.30418 and earlier versions have a Buffer Errors vulnerability. Successful exploitation could lead to arbitrary code execution in the context of the current user.
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Analysis
by VulDB Data Team • 08/10/2024
Adobe Acrobat and Reader versions prior to 2018.011.20040, 2017.011.30080, and 2015.006.30418 contain a buffer overflow vulnerability that stems from improper input validation when processing maliciously crafted pdf files. This vulnerability falls under the CWE-121 buffer overflow category and represents a critical security flaw that enables remote code execution. The flaw occurs during the parsing of pdf objects where insufficient bounds checking allows attackers to overwrite adjacent memory locations. When a user opens a maliciously crafted pdf file, the application fails to properly validate the size of data structures before copying data into fixed-size buffers, creating opportunities for attackers to inject and execute arbitrary code within the context of the current user. This vulnerability directly maps to attack techniques described in the ATT&CK framework under T1203 and T1059, where adversaries leverage software vulnerabilities to execute malicious code. The operational impact is severe as it allows for privilege escalation attacks where an attacker can gain unauthorized access to system resources and potentially compromise the entire system. The vulnerability is particularly dangerous because it requires no special privileges to exploit and can be triggered simply by opening a malicious document, making it a prime target for phishing campaigns and social engineering attacks. The buffer overflow condition creates a predictable memory corruption pattern that can be leveraged to redirect program execution flow, effectively allowing attackers to execute arbitrary commands with the privileges of the affected user. This vulnerability demonstrates the critical importance of input validation in document processing applications and highlights the risks associated with legacy software versions that may not receive timely security updates.
The technical exploitation of this buffer overflow vulnerability requires careful crafting of pdf files that contain oversized data structures designed to overflow the allocated buffers. Attackers typically construct malicious pdf documents that include specially formatted objects with excessive data lengths, causing the application to write beyond the intended memory boundaries. The memory corruption occurs in the pdf parsing routines where string handling and object size calculations are not properly validated, allowing for stack or heap corruption. This type of vulnerability is classified as a classic buffer overflow and represents a fundamental flaw in memory management practices within the application's pdf processing engine. The exploitability of this vulnerability is further enhanced by the fact that pdf readers are commonly used applications that are frequently opened by users without security awareness. The security implications extend beyond simple code execution as the vulnerability can be chained with other exploits to bypass modern security mechanisms such as stack canaries, address space layout randomization, and data execution prevention. Organizations should prioritize immediate patching of affected systems, as this vulnerability has been actively exploited in the wild. The mitigation strategy involves not only applying security patches but also implementing document inspection policies and user education programs to reduce the risk of encountering malicious pdf files. Security teams should also consider network-based detection measures to identify and block suspicious pdf file transfers, particularly in environments where pdf documents are frequently exchanged. The vulnerability serves as a reminder of the critical need for continuous security monitoring and rapid response to emerging threats in document processing applications.