CVE-2015-5793 in iTunes
Summary
by MITRE
WebKit, as used in JavaScriptCore in Apple iOS before 9 and iTunes before 12.3, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted web site, a different vulnerability than other WebKit CVEs listed in APPLE-SA-2015-09-16-1 and APPLE-SA-2015-09-16-3.
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Analysis
by VulDB Data Team • 06/18/2022
CVE-2015-5793 represents a critical memory corruption vulnerability within WebKit's JavaScriptCore engine that affected Apple iOS versions prior to 9 and iTunes versions prior to 12.3. This vulnerability resides in the JavaScriptCore JavaScript engine component that powers web content rendering and script execution within Apple's ecosystem. The flaw manifests when processing specially crafted web content that triggers improper memory handling during JavaScript object manipulation and garbage collection processes. The vulnerability is particularly dangerous because it operates at the intersection of web rendering and scripting execution, creating a pathway for remote code execution through malicious websites that can be accessed by unsuspecting users.
The technical implementation of this vulnerability stems from insufficient input validation and memory management within JavaScriptCore's object allocation and deallocation mechanisms. When the engine processes malformed JavaScript objects or executes specific sequences of operations on heap-allocated memory structures, it fails to properly validate memory boundaries and object references. This leads to memory corruption that can be exploited to overwrite critical memory locations or manipulate execution flow. The vulnerability operates under CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write conditions, both of which are common entry points for arbitrary code execution exploits. Attackers can leverage this flaw by crafting malicious web pages that, when loaded in a vulnerable browser or webview, trigger the memory corruption through specific JavaScript operations that cause the engine to access invalid memory addresses.
The operational impact of CVE-2015-5793 extends beyond simple application crashes to enable full remote code execution capabilities. An attacker controlling a malicious website can deliver payloads that exploit the memory corruption to execute arbitrary code with the privileges of the compromised application. This represents a significant escalation from typical denial of service conditions, as the vulnerability allows for complete system compromise when the target application is running with elevated privileges. The vulnerability's exploitation can lead to persistent backdoors, data exfiltration, and complete system takeover. This aligns with ATT&CK technique T1059.007 for JavaScript and T1059.008 for PowerShell, which cover execution through scripting languages and command and control communication. The attack surface is particularly broad as it affects not only iOS devices but also iTunes installations, creating multiple potential entry points for attackers targeting Apple ecosystem users.
Mitigation strategies for CVE-2015-5793 require immediate patch deployment and system updates to address the underlying memory corruption in JavaScriptCore. Apple released security updates for iOS 9 and iTunes 12.3 that fixed the vulnerability through improved memory validation and heap management within the JavaScript engine. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly. Network-based mitigations include web filtering solutions that can block access to known malicious domains and content that might exploit this vulnerability. Browser security enhancements such as sandboxing and memory protection mechanisms should be enabled to limit the impact of successful exploitation attempts. Additionally, user education regarding safe browsing practices and the avoidance of untrusted websites remains crucial in reducing the attack surface. The vulnerability demonstrates the importance of secure coding practices in JavaScript engines and the need for continuous security auditing of core system components that handle untrusted input from web sources.