CVE-2016-0973 in Flash Player
Summary
by MITRE • 01/26/2023
Use-after-free vulnerability in the URLRequest object implementation in Adobe Flash Player before 18.0.0.329 and 19.x and 20.x before 20.0.0.306 on Windows and OS X and before 11.2.202.569 on Linux, Adobe AIR before 20.0.0.260, Adobe AIR SDK before 20.0.0.260, and Adobe AIR SDK & Compiler before 20.0.0.260 allows attackers to execute arbitrary code via a URLLoader.load call, a different vulnerability than CVE-2016-0974, CVE-2016-0975, CVE-2016-0982, CVE-2016-0983, and CVE-2016-0984.
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Analysis
by VulDB Data Team • 01/26/2023
The CVE-2016-0973 vulnerability represents a critical use-after-free flaw within Adobe Flash Player's URLRequest object implementation that affects multiple versions across different operating systems. This vulnerability resides in the core networking functionality of Flash Player, specifically within how the URLLoader class handles asynchronous network requests. The flaw manifests when a URLLoader.load call is executed followed by improper memory management, creating conditions where freed memory locations can be accessed and manipulated by malicious code. The vulnerability is particularly dangerous because it operates at the core level of Flash Player's networking stack, making it an attractive target for exploitation in web-based attacks.
The technical implementation of this use-after-free vulnerability stems from inadequate memory management practices within the URLRequest object's lifecycle. When a URLLoader.load operation completes, the underlying memory structures associated with the request may be freed while references to those structures still exist in the application's memory space. This creates a window where attackers can manipulate the freed memory locations through carefully crafted input data, potentially leading to memory corruption that can be leveraged for code execution. The vulnerability is classified under CWE-416 as a use-after-free condition, which is a well-documented pattern that has historically resulted in numerous security incidents across various software platforms. The specific nature of this flaw means that attackers do not need to directly exploit the memory corruption but can instead manipulate the application's behavior through indirect memory manipulation techniques.
The operational impact of this vulnerability extends across multiple platforms including Windows, OS X, and Linux, with affected versions spanning Flash Player 18.0.0.328 and earlier, Flash Player 19.x and 20.x versions prior to 20.0.0.306, and Adobe AIR versions before 20.0.0.260. This broad scope means that the vulnerability affects a significant portion of the Flash ecosystem, potentially exposing millions of users to remote code execution risks. Attackers can leverage this vulnerability through web browsers that have Flash Player enabled, making it particularly dangerous in enterprise environments where users frequently access untrusted websites. The vulnerability's classification aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would allow attackers to execute arbitrary code on affected systems with the privileges of the Flash Player process. The exploitation typically involves crafting malicious SWF files that trigger the vulnerable code path when loaded in a browser, making this a prime example of a client-side attack vector that can bypass traditional network security measures.
Mitigation strategies for CVE-2016-0973 primarily focus on immediate patching and operational security measures. Organizations should prioritize updating all affected versions of Adobe Flash Player, Adobe AIR, and related SDKs to their patched versions, with the specific version numbers provided in the vulnerability advisory. System administrators should implement network-level controls to restrict Flash Player usage and consider disabling Flash content entirely in browser environments where possible. The vulnerability's nature makes it particularly susceptible to exploitation through drive-by download scenarios, so implementing web application firewalls and content filtering solutions can provide additional protection layers. Security teams should also monitor for indicators of compromise related to this vulnerability, including unusual network connections or memory access patterns that might indicate exploitation attempts. Regular security assessments of Flash Player usage within the organization can help identify legacy applications that may still be vulnerable and require additional mitigation strategies. The remediation process should also include user education about the risks associated with Flash Player and the importance of keeping software updated, as many successful exploits rely on users unknowingly visiting malicious websites that leverage these vulnerabilities.