CVE-2017-2495 in Safari
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.3.2 is affected. Safari before 10.1.1 is affected. The issue involves the "Safari" component. It allows remote attackers to cause a denial of service (application crash) via a crafted web site that improperly interacts with the history menu.
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Analysis
by VulDB Data Team • 12/24/2020
This vulnerability resides within Apple's Safari web browser component affecting iOS versions prior to 10.3.2 and Safari versions before 10.1.1. The flaw manifests as a denial of service condition that can be triggered remotely through maliciously crafted web content. The vulnerability specifically targets the interaction between web pages and Safari's history menu functionality, creating a scenario where legitimate web content can cause the browser application to crash unexpectedly. This represents a classic buffer over-read or improper input validation issue that occurs when the browser fails to properly handle malformed history menu interactions.
The technical nature of this vulnerability falls under CWE-125, which describes out-of-bounds read conditions where an application attempts to read memory beyond the bounds of a buffer. In this case, the buffer in question relates to how Safari processes history menu elements when presented with crafted web content. The improper interaction with the history menu suggests that the vulnerability stems from insufficient bounds checking or validation of user-provided data that influences the browser's navigation history handling mechanisms. Attackers can exploit this by constructing web pages that manipulate the history menu in ways that cause memory access violations or stack corruption within the Safari rendering engine.
From an operational perspective, this vulnerability enables remote attackers to disrupt user browsing sessions by causing Safari to crash and restart. The impact extends beyond simple inconvenience to potential security implications, as application crashes can sometimes be leveraged as precursors to more sophisticated attacks or can be used to exhaust system resources through repeated exploitation attempts. Users who visit compromised websites may experience unexpected browser shutdowns, leading to loss of unsaved work or session data, while also potentially creating opportunities for attackers to gather information about the target system through crash analysis. The remote exploitation aspect means that users do not need to download or execute anything beyond visiting a malicious website, making this particularly dangerous in phishing campaigns or compromised advertising networks.
Mitigation strategies should focus on immediate patch deployment for all affected iOS and Safari versions, with particular attention to organizations that may have legacy systems or restricted update mechanisms. System administrators should implement web content filtering solutions that can block known malicious domains and monitor for suspicious web traffic patterns. Additionally, users should be educated about the importance of keeping their systems updated and avoiding untrusted websites. The vulnerability demonstrates the importance of input validation in web browser components and highlights the need for comprehensive security testing of user interaction elements, particularly those that maintain persistent state like browser history menus. Organizations should also consider implementing sandboxing measures and browser hardening configurations to limit the potential impact should similar vulnerabilities be discovered in the future.