CVE-2017-14149 in GoAhead
Summary
by MITRE
GoAhead 3.4.0 through 3.6.5 has a NULL Pointer Dereference in the websDecodeUrl function in http.c, leading to a crash for a "POST / HTTP/1.1" request.
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Analysis
by VulDB Data Team • 11/13/2019
The vulnerability identified as CVE-2017-14149 represents a critical null pointer dereference flaw within the GoAhead web server software version 3.4.0 through 3.6.5. This issue manifests specifically within the websDecodeUrl function located in the http.c source file, creating a condition where the application fails to properly validate input parameters before attempting to dereference a null pointer. The vulnerability is particularly concerning as it can be triggered through a simple HTTP POST request directed at the root endpoint with the request line format "POST / HTTP/1.1", making it easily exploitable by remote attackers without requiring any authentication or privileged access. The flaw stems from inadequate input validation mechanisms that fail to check whether certain pointer variables have been properly initialized before being accessed, creating a classic scenario for denial of service attacks. This type of vulnerability falls under the CWE-476 category of NULL Pointer Dereference, which is classified as a fundamental programming error that can lead to application crashes and system instability. The impact of this vulnerability extends beyond simple service disruption as it can be leveraged by malicious actors to perform automated scanning and enumeration activities, potentially identifying other weaknesses in the target system infrastructure. From an operational perspective, the vulnerability exposes systems running affected GoAhead versions to potential denial of service conditions that could be exploited at scale, particularly in environments where the web server handles high volumes of incoming requests. The ATT&CK framework categorizes this vulnerability under the T1499.004 technique for Network Denial of Service, as it enables adversaries to disrupt network services through controlled resource consumption or system instability. The technical exploitation requires minimal effort from attackers, as the specific request format is well-defined and can be automated through simple scripting tools. Organizations running vulnerable versions of GoAhead should consider immediate patching or mitigation strategies, as the vulnerability affects a widely deployed web server implementation. The flaw demonstrates the importance of proper input validation and defensive programming practices, particularly in network-facing applications where malformed requests can lead to system instability. Security teams should implement network monitoring to detect unusual request patterns that might indicate exploitation attempts, while also conducting comprehensive inventory audits to identify all systems running vulnerable GoAhead versions.
The vulnerability's exploitation mechanism relies on the web server's failure to properly handle malformed URL decoding requests, specifically when processing POST requests to the root endpoint. When the websDecodeUrl function receives a specially crafted request, it attempts to access memory locations through uninitialized or null pointer references, causing the application process to terminate unexpectedly. This behavior aligns with the CWE-476 classification and represents a fundamental flaw in the software's defensive programming approach. The impact of this vulnerability extends beyond immediate service disruption, as it can be used as a reconnaissance tool to identify vulnerable systems within a network perimeter. Security professionals should note that this vulnerability can be chained with other exploits to create more sophisticated attack vectors, particularly when combined with information disclosure or privilege escalation vulnerabilities. The affected versions span a significant release range, indicating that the flaw was present for an extended period and likely affected numerous production systems. Organizations should prioritize patch management processes to address this vulnerability, as the null pointer dereference creates a reliable method for causing service interruptions. The vulnerability's presence in widely used web server software underscores the importance of maintaining current security patches and implementing robust application security testing procedures. From a compliance standpoint, this vulnerability could potentially violate various security standards including iso 27001, nist 800-53, and pci dss requirements for maintaining secure system configurations and addressing known vulnerabilities in a timely manner. The technical implementation of the fix typically involves adding proper null pointer checks before any pointer dereference operations, ensuring that all input parameters are validated and initialized appropriately. Network administrators should consider implementing request rate limiting and access control measures to reduce the effectiveness of automated exploitation attempts while monitoring for unusual patterns that might indicate attempted exploitation.