CVE-2017-16364 in Acrobat Reader
Summary
by MITRE
An issue was discovered in Adobe Acrobat and Reader: 2017.012.20098 and earlier versions, 2017.011.30066 and earlier versions, 2015.006.30355 and earlier versions, and 11.0.22 and earlier versions. This issue is due to an untrusted pointer dereference when handling number format dictionary entries. In this scenario, the input is crafted in way that the computation results in pointers to memory locations that do not belong to the relevant process address space. The dereferencing operation is a read operation, and an attack can result in sensitive data exposure.
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Analysis
by VulDB Data Team • 09/04/2024
This vulnerability exists in Adobe Acrobat and Reader across multiple version ranges including 2017.012.20098 and earlier, 2017.011.30066 and earlier, 2015.006.30355 and earlier, and 11.0.22 and earlier versions. The flaw manifests as an untrusted pointer dereference during the processing of number format dictionary entries within the PDF parsing functionality. This represents a classic memory safety issue where the application fails to properly validate pointer values before attempting to access memory locations. The vulnerability stems from insufficient input validation mechanisms that allow crafted malicious PDF files to manipulate the parsing logic in ways that cause the software to attempt reading from arbitrary memory addresses.
The technical implementation of this vulnerability involves a specific pointer arithmetic operation that results in memory addresses outside the legitimate process address space. When the PDF parser encounters specially crafted number format dictionary entries, the mathematical computations used to determine pointer values produce results that point to memory locations belonging to other processes or system memory regions. This untrusted pointer dereference occurs during a read operation, meaning that an attacker can potentially extract sensitive data from memory locations that should remain protected. The vulnerability specifically affects the parsing and handling of number format dictionaries which are used to define numerical formatting rules in PDF documents, making it particularly dangerous when processing documents from untrusted sources.
From an operational impact perspective, this vulnerability creates a significant risk for organizations that rely on Adobe Acrobat and Reader for document processing. An attacker could craft malicious PDF files that, when opened by vulnerable software versions, would trigger the pointer dereference and potentially expose sensitive information stored in memory. This includes but is not limited to user credentials, personal data, corporate confidential information, or system memory contents. The attack requires the victim to open a specifically crafted PDF document, making it a typical client-side exploitation vector. The vulnerability's classification as an untrusted pointer dereference aligns with CWE-476 which describes NULL pointer dereference conditions, though this variant specifically involves invalid pointer arithmetic rather than null pointer access. This type of vulnerability falls under the ATT&CK technique T1059.007 for exploitation of client-side applications and represents a common vector for data exfiltration attacks.
Organizations should immediately update to patched versions of Adobe Acrobat and Reader to mitigate this vulnerability. The recommended mitigation strategy includes deploying security patches provided by Adobe as soon as they become available, implementing strict document validation policies for incoming PDF files, and considering sandboxing mechanisms for PDF processing. Network-level protections such as PDF content filtering and application whitelisting can provide additional defense in depth. Security monitoring should focus on detecting attempts to open suspicious PDF files, particularly those with unusual number format dictionary entries. The vulnerability demonstrates the importance of robust input validation and memory safety practices in document processing software, highlighting the need for comprehensive security testing of parsing components that handle untrusted data. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates across all affected systems.