CVE-2005-0492 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat Reader 6.0.3 and 7.0.0 allows remote attackers to cause a denial of service (application crash) via a PDF file that contains a negative Count value in the root page node.
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Analysis
by VulDB Data Team • 06/08/2019
Adobe Acrobat Reader versions 6.0.3 and 7.0.0 contain a critical buffer overflow vulnerability that stems from insufficient input validation in the PDF parsing engine. This vulnerability manifests when the application encounters a maliciously crafted PDF file containing a negative Count value within the root page node structure. The flaw represents a classic case of improper boundary checking and integer validation that falls under CWE-129, which addresses insufficient validation of length values. The root cause lies in the application's failure to properly validate integer values before using them as array indices or buffer sizes, creating a scenario where a negative integer can be interpreted as a valid array length parameter.
The operational impact of this vulnerability extends beyond simple application instability, as it provides remote attackers with a reliable method to execute denial of service attacks against systems running affected versions of Adobe Acrobat Reader. When the application processes a PDF file with a negative Count value, the parsing routine attempts to allocate memory or iterate through arrays using this invalid negative value, leading to memory corruption and subsequent application crash. This behavior aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through malformed input. The vulnerability specifically targets the document object model parsing functionality within the PDF engine, where the application fails to implement proper input sanitization before processing structural elements of the PDF file format.
Attackers can exploit this vulnerability by crafting a malicious PDF file that contains a negative integer value in the Count field of the root page node, typically found within the document catalog structure. Upon opening such a file, the Acrobat Reader application will attempt to process the invalid Count value, resulting in a segmentation fault or access violation that terminates the application. This vulnerability affects not only individual users but also enterprise environments where Acrobat Reader is widely deployed, potentially enabling attackers to disrupt business operations through targeted denial of service attacks. The exploitation requires no special privileges and can be executed through simple web-based attacks or email attachments, making it particularly dangerous in corporate environments. Organizations should immediately implement patch management procedures to upgrade to Adobe Acrobat Reader versions that properly validate Count values and prevent negative integers from being processed as valid array lengths. Additionally, network security controls such as PDF content filtering and application whitelisting can provide additional layers of protection against exploitation attempts.