CVE-2014-3620 in cURL
Summary
by MITRE
cURL and libcurl before 7.38.0 allow remote attackers to bypass the Same Origin Policy and set cookies for arbitrary sites by setting a cookie for a top-level domain.
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Analysis
by VulDB Data Team • 02/04/2019
The vulnerability identified as CVE-2014-3620 affects cURL and libcurl versions prior to 7.38.0, representing a critical security flaw that undermines fundamental web security mechanisms. This issue specifically targets the Same Origin Policy implementation within these widely-used HTTP client libraries, which are integral components of countless applications and systems across the internet infrastructure. The vulnerability allows remote attackers to exploit cookie handling mechanisms in a manner that circumvents browser security controls designed to prevent cross-site scripting attacks and unauthorized data manipulation. The flaw stems from improper validation of cookie domains, particularly when dealing with top-level domains, creating a pathway for malicious actors to inject cookies into contexts where they should not be permitted.
The technical root cause of this vulnerability lies in how cURL and libcurl process cookie domain attributes when multiple cookies are set for the same top-level domain. When a cookie is set for a domain such as .example.com, the library fails to properly enforce domain boundaries, allowing cookies to be set for completely different domains within the same top-level namespace. This behavior violates the fundamental principles of web security protocols and enables attackers to manipulate cookie storage in ways that bypass standard security restrictions. The flaw operates at the HTTP cookie management level, where the software incorrectly interprets domain matching rules, leading to improper cookie validation and storage. This issue is categorized under CWE-284 Access Control Bypass, which specifically addresses situations where access controls are improperly enforced, and aligns with ATT&CK technique T1531 Credential Access through cookie manipulation.
The operational impact of this vulnerability extends far beyond simple cookie manipulation, as it creates potential pathways for session hijacking, cross-site request forgery attacks, and unauthorized data access across different domains. Attackers can exploit this weakness to set malicious cookies for sites within the same top-level domain, potentially enabling them to impersonate users across multiple related services or applications. The consequences are particularly severe because cURL and libcurl are used extensively in server-side applications, automated scripts, web scraping tools, and various network utility programs that handle authentication and session management. Organizations using vulnerable versions of these libraries face significant risk of unauthorized access to user sessions, data breaches, and potential compromise of sensitive information. The vulnerability affects not only web applications but also any system that relies on cURL or libcurl for HTTP communications, making it a widespread concern across the software ecosystem.
Mitigation of this vulnerability requires immediate upgrade to cURL and libcurl versions 7.38.0 or later, where the cookie handling logic has been corrected to properly enforce domain boundaries and Same Origin Policy restrictions. Security administrators should conduct comprehensive inventory audits to identify all systems and applications using vulnerable versions of these libraries, particularly focusing on server-side components, automated data processing tools, and any custom applications that may be leveraging cURL functionality. The remediation process should include not only software updates but also thorough security testing to ensure that existing cookie handling mechanisms function correctly after the upgrade. Organizations should implement monitoring solutions to detect anomalous cookie behavior patterns and establish incident response procedures for potential exploitation attempts. Additionally, developers should review their applications for proper cookie management practices and consider implementing additional security layers such as secure cookie attributes, proper domain validation, and comprehensive input sanitization to further reduce attack surface and protect against similar vulnerabilities in the future.