CVE-2009-2058 in Safari
Summary
by MITRE
Apple Safari before 3.2.2 uses the HTTP Host header to determine the context of a document provided in a (1) 4xx or (2) 5xx CONNECT response from a proxy server, which allows man-in-the-middle attackers to execute arbitrary web script by modifying this CONNECT response, aka an "SSL tampering" attack.
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Analysis
by VulDB Data Team • 09/06/2019
The vulnerability described in CVE-2009-2058 represents a critical security flaw in Apple Safari browsers prior to version 3.2.2 that fundamentally undermines the integrity of secure web communications. This issue stems from Safari's improper handling of HTTP Host headers within proxy server responses, specifically when encountering 4xx or 5xx status codes during CONNECT requests. The flaw creates a dangerous condition where the browser's security model becomes vulnerable to manipulation through carefully crafted proxy responses, effectively allowing malicious actors to compromise the SSL/TLS security assurances that users expect when browsing the internet.
The technical implementation of this vulnerability occurs at the intersection of HTTP proxy protocols and SSL certificate validation mechanisms. When Safari encounters a CONNECT response from a proxy server, it relies on the Host header value to determine the appropriate context for document handling. This reliance creates an attack surface where an attacker positioned between the user and the target server can intercept the proxy response and modify the Host header value. The vulnerability specifically affects responses with status codes 4xx and 5xx, which typically indicate client or server errors, but the flaw allows these error responses to be manipulated in ways that bypass normal security checks. This represents a classic case of improper input validation where the browser fails to properly sanitize or verify the Host header information before using it to establish secure communication context.
The operational impact of this vulnerability is severe and multifaceted, creating multiple attack vectors for man-in-the-middle adversaries. An attacker can exploit this weakness to inject arbitrary web scripts into the browser context, effectively bypassing SSL certificate validation and potentially gaining access to sensitive user data, session information, or other confidential communications. The attack requires the attacker to be positioned in the network path between the user and the target server, typically through network interception or compromised proxy infrastructure. This vulnerability particularly affects users who rely on proxy servers for internet access, as the attack can be executed through compromised or malicious proxy configurations. The implications extend beyond simple script execution to potentially enable full session hijacking, credential theft, and other advanced persistent threats that could compromise user privacy and security.
From a cybersecurity framework perspective, this vulnerability maps directly to CWE-200, which addresses "Information Exposure," and CWE-310, which covers "Cryptographic Issues." The attack pattern aligns with ATT&CK technique T1041, "Exfiltration Over C2 Channel," and T1566, "Phishing," as it enables attackers to craft convincing malicious web content that appears legitimate to users. The vulnerability also demonstrates characteristics of T1190, "Exploit Public-Facing Application," since it affects a widely used web browser application that users interact with regularly. Organizations should implement immediate mitigations including updating to Safari 3.2.2 or later versions, implementing network monitoring for suspicious proxy behavior, and deploying security solutions that can detect and prevent unauthorized modifications to HTTP headers. Additionally, users should be educated about the risks of using untrusted proxy servers and the importance of maintaining up-to-date browser software to protect against such exploitation vectors.