CVE-2016-7656 in iCloud
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.2 is affected. Safari before 10.0.2 is affected. iCloud before 6.1 is affected. iTunes before 12.5.4 is affected. The issue involves the "WebKit" component. It allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted web site.
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Analysis
by VulDB Data Team • 10/07/2022
The vulnerability identified as CVE-2016-7656 represents a critical memory corruption flaw within Apple's WebKit rendering engine that affected multiple Apple products including iOS versions prior to 10.2, Safari versions before 10.0.2, iCloud versions before 6.1, and iTunes versions before 12.5.4. This vulnerability resides in the core web rendering component that processes web content across Apple's ecosystem, making it particularly dangerous as it could be exploited through standard web browsing activities. The flaw specifically manifests as a heap-based buffer overflow or memory corruption issue that occurs when processing maliciously crafted web content, allowing attackers to manipulate memory addresses and execute arbitrary code on affected systems.
The technical nature of this vulnerability falls under CWE-125, which describes out-of-bounds read conditions where a program reads data past the end of a valid buffer, and potentially CWE-787, which covers out-of-bounds write operations that can lead to memory corruption. Attackers could exploit this weakness by hosting malicious web content on compromised websites or through phishing campaigns that would automatically trigger the memory corruption when users visited these sites. The exploitation process typically involves crafting specific HTML elements or JavaScript code that would cause the WebKit engine to improperly handle memory allocation during page rendering, leading to controlled memory corruption that could be leveraged for privilege escalation or complete system compromise.
The operational impact of CVE-2016-7656 extends beyond simple application crashes, as it provides attackers with the capability to execute arbitrary code remotely without user interaction, making it particularly dangerous in targeted attack scenarios. This vulnerability could enable threat actors to gain persistent access to affected devices, potentially leading to data exfiltration, keylogger installation, or further network reconnaissance activities. The widespread nature of WebKit's usage across Apple's products means that exploitation could occur through multiple vectors including web browsing, email clients, and cloud synchronization services, creating numerous attack surfaces for potential compromise.
Mitigation strategies for this vulnerability required immediate patching of affected Apple products through official software updates, as Apple released security updates for iOS 10.2, Safari 10.0.2, iCloud 6.1, and iTunes 12.5.4 to address the memory corruption issues. Security professionals recommended implementing network-based protections such as web application firewalls and content filtering solutions to block access to known malicious domains, while also enforcing strict browser security policies including sandboxing and privilege separation. The vulnerability also highlighted the importance of keeping all software components updated, as it demonstrated how a single component flaw could impact an entire ecosystem of products. Organizations should have implemented automated patch management systems to ensure rapid deployment of security updates, while also conducting vulnerability assessments to identify any potential exploitation attempts. The incident underscored the need for continuous monitoring of security advisories and the importance of maintaining up-to-date threat intelligence to detect and respond to similar vulnerabilities in the future.