CVE-2017-16360 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 vulnerability is an instance of a use after free vulnerability in the MakeAccessible plugin, when creating an internal data structure. The mismatch between an old and a new object can provide an attacker with unintended memory access -- potentially leading to code corruption, control-flow hijack, or an information leak attack. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 01/24/2021
This vulnerability resides within Adobe Acrobat and Reader software across multiple version ranges, specifically affecting versions up to and including 2017.012.20098, 2017.011.30066, 2015.006.30355, and 11.0.22. The flaw manifests in the MakeAccessible plugin which is responsible for creating accessible versions of pdf documents for users with disabilities. The vulnerability represents a classic use after free condition that occurs during the creation of internal data structures, making it particularly dangerous as it allows for memory corruption and potential code execution. This type of vulnerability falls under the CWE-416 category of use after free conditions, where memory that has been freed is accessed again, creating opportunities for attackers to manipulate program execution flow.
The technical nature of this vulnerability stems from improper memory management within the plugin's internal data structure creation process. When the MakeAccessible plugin handles document processing, it creates and manages memory objects that are subsequently freed but not properly invalidated. An attacker can manipulate the input data to cause the plugin to reference freed memory locations, leading to a mismatch between old and new objects in memory. This memory inconsistency can be exploited to either corrupt program control flow, redirect execution to malicious code, or extract sensitive information from memory. The vulnerability's exploitation potential aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary code within the context of the affected application.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with a pathway to achieve arbitrary code execution within the context of the Acrobat Reader application. This represents a significant security risk since Acrobat Reader is frequently used to open documents from untrusted sources, making it a prime target for social engineering attacks. Attackers could craft malicious pdf documents that, when opened, trigger the vulnerable code path and execute malicious payloads without requiring user interaction beyond opening the file. The vulnerability's exploitation could result in complete system compromise, especially when combined with other attack vectors or when targeting systems with less security hardening. Organizations relying on Acrobat Reader for document processing face potential data breaches, system infiltration, and lateral movement opportunities for attackers who successfully exploit this flaw.
Mitigation strategies should focus on immediate patching of affected versions, as Adobe released security updates addressing this vulnerability. Organizations should implement application whitelisting policies to restrict execution of untrusted pdf files and deploy sandboxing solutions to isolate pdf processing activities. Network segmentation and monitoring for suspicious pdf file handling activities can provide additional layers of defense. Security teams should also consider disabling the MakeAccessible plugin if it is not essential for their operations, as this eliminates the attack surface associated with this specific vulnerability. Regular security assessments and vulnerability scanning should be conducted to identify other potential use after free conditions within the application ecosystem, as these types of memory corruption vulnerabilities often indicate broader memory management issues that may exist in other components of the software stack.