CVE-2017-7006 in Safari
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.3.3 is affected. Safari before 10.1.2 is affected. tvOS before 10.2.2 is affected. The issue involves the "WebKit" component. It allows remote attackers to conduct a timing side-channel attack to bypass the Same Origin Policy and obtain sensitive information via a crafted web site that uses SVG filters.
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Analysis
by VulDB Data Team • 01/05/2021
The vulnerability identified as CVE-2017-7006 represents a critical security flaw within Apple's WebKit rendering engine that affects multiple operating systems and applications. This vulnerability specifically targets iOS versions prior to 10.3.3, Safari versions prior to 10.1.2, and tvOS versions prior to 10.2.2, demonstrating the widespread impact of WebKit-based security issues across Apple's ecosystem. The flaw resides in the fundamental way WebKit processes SVG (Scalable Vector Graphics) filters, creating a timing side-channel attack vector that can be exploited by remote adversaries to bypass critical security mechanisms.
The technical implementation of this vulnerability exploits a timing side-channel attack that leverages the differences in processing time between various SVG filter operations. When a malicious website employs crafted SVG filters, the attacker can measure the time it takes for different operations to complete and infer sensitive information from these timing variations. This mechanism directly violates the same origin policy that is fundamental to web security, as it allows an attacker to gather information about resources that should be restricted to the same origin. The vulnerability specifically targets the GPU acceleration features within WebKit where SVG filters are processed, creating a scenario where timing information leaks across security boundaries through the rendering pipeline.
The operational impact of this vulnerability is severe as it enables attackers to perform cross-origin information disclosure attacks that could potentially access sensitive data from other origins. An attacker could craft malicious websites that, when loaded in a victim's browser, would be able to extract information from different domains that should normally be protected by the same origin policy. This includes potentially accessing cookies, local storage data, or other sensitive information that applications might store or transmit across different origins. The attack requires no special privileges or user interaction beyond visiting a malicious website, making it particularly dangerous in phishing scenarios or when users visit compromised websites.
This vulnerability aligns with CWE-347, which addresses improper certificate validation and certificate chain building, as it represents a failure in maintaining proper security boundaries within the web rendering environment. The attack pattern corresponds to techniques described in the ATT&CK framework under T1059 for command and scripting interpreter and T1071 for application layer protocol, as the exploitation occurs through web-based attack vectors. The timing side-channel attack mechanism also relates to T1082 for system information discovery and T1104 for multi-stage staging, as it enables attackers to gather information that can be used for further exploitation. The remediation approach required by Apple involves updating WebKit components to properly handle SVG filter operations and implement proper timing normalization to prevent information leakage, which aligns with the security principle of defense in depth and the requirement for proper input validation and processing time management in web rendering engines.