CVE-2008-3746 in neon
Summary
by MITRE
neon 0.28.0 through 0.28.2 allows remote servers to cause a denial of service (NULL pointer dereference and crash) via vectors related to Digest authentication, Digest domain parameter support, and the parse_domain function.
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Analysis
by VulDB Data Team • 08/17/2019
The vulnerability identified as CVE-2008-3746 affects the neon library version 0.28.0 through 0.28.2, presenting a critical denial of service risk that can be exploited by remote servers. This flaw manifests through multiple attack vectors involving Digest authentication mechanisms, specifically targeting the handling of Digest domain parameters and the parse_domain function. The vulnerability represents a classic example of a null pointer dereference flaw that can be triggered during normal network operations, making it particularly dangerous in production environments where such authentication mechanisms are commonly employed.
The technical implementation of this vulnerability stems from inadequate input validation within the Digest authentication processing code of the neon library. When remote servers present malformed or crafted Digest authentication headers containing invalid domain parameters, the parse_domain function fails to properly handle null references, leading to a crash of the affected application. This behavior aligns with CWE-476 which specifically addresses null pointer dereference vulnerabilities, where a null reference is dereferenced without proper validation. The flaw occurs during the authentication negotiation phase when the library attempts to parse and validate domain information provided by the server, creating an execution path that leads to memory access violations.
From an operational perspective, this vulnerability poses significant risks to systems that rely on the neon library for HTTP communications, particularly web applications, proxies, and client software that implement Digest authentication. Attackers can exploit this weakness by setting up malicious servers that respond with specially crafted Digest authentication headers, causing any application using the vulnerable version of neon to crash and become unavailable. The impact extends beyond simple service disruption as the crash can occur during legitimate user interactions, potentially leading to extended downtime and service unavailability that affects business operations and user experience. This vulnerability directly maps to attack techniques described in the ATT&CK framework under the T1499 category for network denial of service attacks, where adversaries leverage software flaws to disrupt system availability.
The mitigation strategy for CVE-2008-3746 requires immediate upgrading of the neon library to version 0.28.3 or later, where the null pointer dereference issues have been addressed through proper input validation and error handling. Organizations should conduct thorough inventory assessments to identify all systems utilizing vulnerable versions of the library and implement patch management procedures to ensure timely remediation. Additionally, network monitoring should be enhanced to detect unusual authentication header patterns that might indicate exploitation attempts, while defensive measures such as implementing authentication header validation rules can provide additional layers of protection. The fix implemented in the patched versions demonstrates proper error handling practices that align with secure coding guidelines, ensuring that null references are checked before dereferencing and that appropriate error conditions are handled gracefully rather than allowing crashes to occur.