CVE-2015-1222 in Chrome
Summary
by MITRE
Multiple use-after-free vulnerabilities in the ServiceWorkerScriptCacheMap implementation in content/browser/service_worker/service_worker_script_cache_map.cc in Google Chrome before 41.0.2272.76 allow remote attackers to cause a denial of service or possibly have unspecified other impact via vectors that trigger a ServiceWorkerContextWrapper::DeleteAndStartOver call, related to the NotifyStartedCaching and NotifyFinishedCaching functions.
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Analysis
by VulDB Data Team • 04/12/2022
The vulnerability described in CVE-2015-1222 represents a critical use-after-free flaw within Google Chrome's ServiceWorker implementation that existed prior to version 41.0.2272.76. This vulnerability specifically affects the ServiceWorkerScriptCacheMap component located in content/browser/service_worker/service_worker_script_cache_map.cc, which serves as a core mechanism for managing cached service worker scripts within the browser's architecture. The flaw manifests when the ServiceWorkerContextWrapper::DeleteAndStartOver function is invoked through specific trigger vectors that involve the NotifyStartedCaching and NotifyFinishedCaching functions, creating a dangerous race condition that can be exploited by remote attackers.
The technical nature of this vulnerability stems from improper memory management within Chrome's service worker caching subsystem where freed memory locations are accessed after being deallocated, leading to potential arbitrary code execution or denial of service conditions. When the NotifyStartedCaching and NotifyFinishedCaching functions are called in sequence, they can cause the ServiceWorkerScriptCacheMap to release memory resources while simultaneously attempting to reference those same memory locations, resulting in use-after-free conditions that can be leveraged to corrupt memory structures. This particular flaw falls under the CWE-416 category of Use After Free, which is classified as a serious memory safety issue that can lead to system compromise. The vulnerability operates at the intersection of web browser architecture and memory management, making it particularly dangerous as it can be triggered through standard web browsing activities without requiring any special privileges or user interaction beyond visiting malicious websites.
The operational impact of CVE-2015-1222 extends beyond simple denial of service scenarios to potentially enable remote code execution attacks that could compromise user systems. Attackers can exploit this vulnerability by crafting malicious web content that triggers the specific sequence of function calls leading to the use-after-free condition, potentially allowing them to execute arbitrary code with the privileges of the Chrome process. This represents a significant threat to user security as it can be exploited through standard web browsing without requiring any additional attack vectors or user interaction. The vulnerability affects the browser's ability to properly manage service worker caching, which is a core feature of modern web applications that enable offline functionality and background processing. The attack surface is particularly concerning as it operates within the browser's core memory management systems, making it difficult to detect and prevent through traditional security measures. According to ATT&CK framework, this vulnerability maps to T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, as the use-after-free condition can potentially be leveraged to gain elevated privileges within the browser environment.
Mitigation strategies for CVE-2015-1222 focus primarily on immediate patching and updating to Chrome versions 41.0.2272.76 or later, which contain the necessary memory management fixes to prevent the use-after-free conditions. Organizations should implement comprehensive browser update policies to ensure all systems are running patched versions, as this vulnerability can be exploited remotely through web content. Additional protective measures include implementing web application firewalls and content filtering systems that can detect and block malicious service worker implementations, though these solutions are less reliable than direct patching. Browser security configurations should be reviewed to disable unnecessary service worker functionality where possible, and security monitoring should be enhanced to detect unusual memory allocation patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper memory management in browser security architectures and demonstrates how seemingly minor implementation flaws can have significant security implications. Regular security assessments of browser components and proactive patch management are essential to prevent exploitation of similar vulnerabilities in the future.