CVE-2008-4812 in Acrobat
Summary
by MITRE
Array index error in Adobe Reader and Acrobat, and the Explorer extension (aka AcroRd32Info), 8.1.2, 8.1.1, and earlier allows remote attackers to execute arbitrary code via a crafted PDF document that triggers an out-of-bounds write, related to parsing of Type 1 fonts.
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Analysis
by VulDB Data Team • 10/15/2018
The vulnerability identified as CVE-2008-4812 represents a critical array index error affecting Adobe Reader and Acrobat software versions 8.1.2 and earlier, along with the AcroRd32Info Explorer extension. This flaw resides in the parsing mechanism for Type 1 fonts within PDF documents, creating a pathway for remote code execution through maliciously crafted PDF files. The issue stems from insufficient bounds checking during font processing operations, specifically when handling Type 1 font data structures that are commonly embedded in PDF documents to ensure proper text rendering across different systems.
The technical nature of this vulnerability aligns with CWE-129, which describes improper validation of array index values, and more specifically with CWE-787, which addresses out-of-bounds write conditions. Attackers can exploit this weakness by constructing a PDF document containing malformed Type 1 font data that triggers an out-of-bounds memory write operation when the vulnerable software attempts to parse and render the font information. This memory corruption occurs during the font processing phase of PDF document rendering, where the application fails to properly validate the size and boundaries of font data arrays before writing to memory locations beyond their allocated bounds.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on Adobe Reader and Acrobat for document processing, as it enables remote code execution without user interaction once a malicious PDF document is opened. The attack vector is particularly dangerous because PDF documents are commonly shared through email attachments, web downloads, and document repositories, making the exploitation surface extremely broad. The vulnerability affects not only desktop users but also enterprise environments where automated PDF processing systems might be compromised, potentially leading to complete system compromise and lateral movement within networks. The exploitability of this vulnerability is enhanced by the widespread use of Adobe Reader across various platforms and the common practice of opening PDF documents without proper sandboxing or security controls.
Organizations should implement immediate mitigations including prompt patching of Adobe Reader and Acrobat to versions 8.1.3 or later, which contain the necessary fixes for this memory corruption issue. Additionally, network administrators should deploy PDF content filtering solutions that can identify and block suspicious PDF files containing malformed font data structures. Security teams should also consider implementing application whitelisting policies that restrict execution of Adobe Reader only from trusted sources and establish network segmentation to limit potential lateral movement if exploitation occurs. The vulnerability demonstrates the importance of maintaining up-to-date software patches and implementing defense-in-depth strategies, as outlined in the MITRE ATT&CK framework under the T1059 technique for command and scripting interpreter, where successful exploitation could enable attackers to execute arbitrary code on target systems. Regular security assessments should include verification of Adobe Reader installations to ensure all systems are patched against this and similar vulnerabilities, particularly given the long lifecycle of enterprise software and the persistent threat landscape targeting document processing applications.