CVE-2015-7023 in Mac OS X
Summary
by MITRE
CFNetwork in Apple iOS before 9.1 and OS X before 10.11.1 does not properly consider the uppercase-versus-lowercase distinction during cookie parsing, which allows remote web servers to overwrite cookies via unspecified vectors.
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Analysis
by VulDB Data Team • 06/24/2022
The vulnerability identified as CVE-2015-7023 represents a significant security flaw in Apple's CFNetwork implementation affecting iOS versions prior to 9.1 and OS X versions prior to 10.11.1. This issue stems from improper handling of case sensitivity during cookie parsing operations, creating a condition where remote web servers can manipulate cookie data through unspecified attack vectors. The flaw fundamentally compromises the integrity of cookie-based session management mechanisms that are critical for maintaining user authentication states and application security boundaries.
The technical implementation flaw resides in CFNetwork's cookie parsing logic which fails to maintain consistent case handling when processing cookie attributes and values. This inconsistency creates a scenario where a malicious server could craft cookie headers with uppercase or lowercase variations that would be incorrectly processed, potentially allowing for cookie overwrites or manipulation. The vulnerability specifically impacts the way the network framework handles cookie attribute parsing, where case-sensitive comparisons should have been enforced but were not properly implemented. This behavior creates a path for attackers to exploit the inconsistent handling of cookie data, particularly when servers send cookie headers that differ in case presentation from what the client expects.
The operational impact of this vulnerability extends beyond simple session management issues to encompass broader security implications for web applications relying on cookie-based authentication. When remote servers can manipulate cookie data through this parsing inconsistency, it creates opportunities for session hijacking, cross-site scripting attacks, and potential privilege escalation scenarios. The unspecified vectors mentioned in the description suggest that attackers could leverage this weakness through various web server configurations or network conditions that trigger the problematic parsing behavior. This vulnerability directly affects the trust model between web clients and servers, undermining the fundamental security assumptions that cookie-based authentication relies upon.
Security practitioners should recognize this vulnerability as a variant of CWE-200, which deals with improper handling of case sensitivity in security-relevant contexts, and it aligns with ATT&CK technique T1185 which covers the exploitation of web application vulnerabilities through cookie manipulation. The fix for this issue required Apple to implement proper case-insensitive handling during cookie attribute parsing while maintaining the security properties necessary for session management. Organizations should prioritize updating affected systems to the patched versions, as the vulnerability creates persistent exposure windows that could be exploited by adversaries with network access to target users. The remediation process involves ensuring that all cookie parsing operations maintain consistent case handling to prevent malicious servers from manipulating client-side cookie storage through crafted header values.