CVE-2017-16384 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. The vulnerability is caused by a buffer over-read in the exif processing module for a PNG file (during XPS conversion). Invalid input leads to a computation where pointer arithmetic results in a location outside valid memory locations belonging to the buffer. An attack can be used to obtain sensitive information, such as object heap addresses, etc.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/24/2021
The vulnerability identified as CVE-2017-16384 represents a critical buffer over-read condition within Adobe Acrobat and Reader applications affecting 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. This flaw exists specifically within the exif processing module responsible for handling PNG files during XPS conversion operations, creating a scenario where maliciously crafted input can trigger memory access violations. The vulnerability stems from improper validation of input data during the processing of embedded exif metadata within PNG file formats, particularly when these files are being converted to XPS document format. The root cause involves pointer arithmetic calculations that exceed the boundaries of allocated memory buffers, leading to unintended memory access patterns. This type of vulnerability falls under the CWE-125 category of Out-of-bounds Read, which is classified as a memory safety issue within the Common Weakness Enumeration framework. The security implications extend beyond simple information disclosure, as the over-read behavior can expose heap memory addresses and other sensitive data structures that may aid in further exploitation attempts.
The operational impact of this vulnerability manifests when a user opens a maliciously crafted PNG file that contains specially constructed exif metadata. During the conversion process to XPS format, the application's exif processing module performs pointer arithmetic operations that traverse beyond the allocated buffer boundaries. This over-read condition allows an attacker to potentially extract information from adjacent memory locations, including heap addresses, stack values, and other sensitive data that may be present in the application's memory space. The vulnerability's exploitation potential aligns with techniques described in the MITRE ATT&CK framework under the T1059.007 sub-technique for 'Command and Scripting Interpreter: PowerShell', as the leaked memory addresses could provide attackers with information needed to bypass security mechanisms or construct more sophisticated attacks. The memory disclosure aspect of this vulnerability is particularly concerning because heap addresses can be leveraged to perform heap spraying attacks or to predict memory layout patterns for exploitation of additional vulnerabilities.
Security researchers have identified that this vulnerability can be exploited through social engineering techniques where users are convinced to open maliciously crafted PNG files, often through email attachments or compromised websites. The attack vector is particularly dangerous because it requires no special privileges or user interaction beyond opening the file, making it an attractive target for initial access vectors in targeted attacks. The vulnerability's presence in multiple versions of Adobe Acrobat and Reader across different product lines indicates a widespread exposure, affecting both enterprise and individual users who may be running outdated software versions. Organizations implementing security controls should consider this vulnerability as part of their broader threat landscape, particularly in environments where users have access to untrusted file formats or where document processing occurs in sensitive contexts. The memory disclosure characteristics make this vulnerability particularly valuable to threat actors seeking to perform advanced exploitation techniques, as the leaked information can be used to defeat modern exploit mitigation mechanisms such as address space layout randomization and stack canaries. This vulnerability demonstrates the importance of proper input validation and memory boundary checking in document processing libraries, as similar issues have been documented in other multimedia processing components within Adobe's product suite and across the industry.