CVE-2017-13793 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11.1 is affected. Safari before 11.0.1 is affected. iCloud before 7.1 on Windows is affected. iTunes before 12.7.1 on Windows is affected. tvOS before 11.1 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 • 01/23/2021
The vulnerability identified as CVE-2017-13793 represents a critical memory corruption flaw within Apple's WebKit rendering engine that affects multiple Apple platforms and applications. This vulnerability resides in the core web browsing component that powers Safari, iOS web views, and various other Apple applications that utilize WebKit for web content rendering. The flaw manifests as a heap-based buffer overflow or memory corruption issue that occurs when processing specially crafted web content, creating a dangerous attack surface for remote threat actors. The vulnerability affects iOS versions prior to 11.1, Safari versions before 11.0.1, iCloud for Windows versions before 7.1, iTunes for Windows versions before 12.7.1, and tvOS versions before 11.1, demonstrating the widespread impact across Apple's ecosystem.
The technical nature of this vulnerability stems from insufficient input validation and memory management within WebKit's JavaScript engine and HTML parser components. Attackers can craft malicious websites containing specially formatted JavaScript code, HTML elements, or multimedia content that triggers the memory corruption when processed by the vulnerable WebKit engine. The flaw typically occurs during the parsing of complex web pages or when executing specific JavaScript operations that lead to improper memory allocation or deallocation. This memory corruption can result in arbitrary code execution with the privileges of the compromised application, potentially allowing attackers to bypass security restrictions and gain unauthorized access to system resources. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write operations, both of which are common manifestations of memory corruption vulnerabilities in web browsers.
The operational impact of CVE-2017-13793 is severe and multifaceted, as it provides attackers with a powerful remote execution vector that can be leveraged across multiple attack surfaces. Organizations and individuals using affected Apple products face significant risk of compromise, as the vulnerability can be exploited through simple web browsing activities without requiring user interaction beyond visiting a malicious website. The potential for denial of service attacks is equally concerning, as the memory corruption can cause applications to crash repeatedly, disrupting normal operations and potentially leading to system instability. The vulnerability's exploitation can result in persistent backdoor access, data theft, or complete system compromise depending on the execution context and target environment. From an adversary perspective, this vulnerability maps to ATT&CK technique T1059.007 for command and control through web shells, and T1203 for legitimate user applications to gain access to system resources, making it particularly dangerous for enterprise environments.
Mitigation strategies for CVE-2017-13793 should focus on immediate patch deployment across all affected Apple platforms and applications, with particular attention to the WebKit component updates. Organizations should implement network-based protections such as web application firewalls and content filtering solutions to block access to known malicious domains that may host exploit code. Browser hardening measures including disabling unnecessary JavaScript features, implementing strict content security policies, and using sandboxing technologies can reduce the attack surface. Regular security assessments and monitoring for suspicious network traffic or system behavior should be conducted to detect potential exploitation attempts. Additionally, user education regarding safe browsing practices and the importance of keeping software updated remains crucial. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date security patches across all system components, particularly those handling untrusted web content, as WebKit vulnerabilities often provide attackers with the most direct path to system compromise in modern computing environments.