CVE-2019-12822 in GoAhead
Summary
by MITRE
In http.c in Embedthis GoAhead before 4.1.1 and 5.x before 5.0.1, a header parsing vulnerability causes a memory assertion, out-of-bounds memory reference, and potential DoS, as demonstrated by a colon on a line by itself.
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Analysis
by VulDB Data Team • 10/05/2023
The vulnerability identified as CVE-2019-12822 represents a critical header parsing flaw within the Embedthis GoAhead web server software affecting versions prior to 4.1.1 and 5.0.1. This issue resides in the http.c component of the web server implementation and demonstrates how seemingly innocuous input can lead to severe system instability. The vulnerability specifically manifests when the web server encounters a colon character on a line by itself within HTTP headers, creating a condition that triggers improper memory handling within the parsing logic. This flaw operates at the protocol level where HTTP header parsing routines fail to properly validate input structure, leading to cascading memory management issues that can compromise the entire server operation.
The technical exploitation of this vulnerability leverages malformed HTTP header content to trigger memory assertion failures and out-of-bounds memory references within the GoAhead web server process. When the server encounters a colon character isolated on a line without proper header field syntax, the parsing routine attempts to access memory locations beyond the allocated buffer boundaries. This memory corruption scenario can occur during normal HTTP request processing when the web server attempts to parse incoming header data. The vulnerability exhibits characteristics consistent with CWE-129, which describes improper validation of length of buffers, and CWE-787, which covers out-of-bounds write operations. The root cause stems from inadequate input sanitization and boundary checking within the header parsing algorithm, allowing malicious or malformed input to disrupt normal program execution flow.
The operational impact of CVE-2019-12822 extends beyond simple service disruption to potentially enable more sophisticated attack vectors. The memory assertion failures and out-of-bounds references create opportunities for denial of service conditions that can render the web server completely unresponsive to legitimate requests. Attackers can exploit this vulnerability by crafting HTTP requests containing the specific malformed header pattern, causing the web server process to crash or become unstable. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and can be leveraged to create persistent service unavailability. The DoS potential is particularly concerning in production environments where web server uptime is critical, as a single malicious request can bring down an entire web application or service.
Organizations utilizing Embedthis GoAhead web server software must implement immediate mitigations to address this vulnerability. The primary recommendation involves upgrading to version 4.1.1 or 5.0.1, which contain patched implementations of the http.c component with proper header validation. Additionally, administrators should consider implementing input validation at the network level through firewalls or reverse proxies to filter out malformed HTTP headers before they reach the vulnerable web server. The mitigation strategy should also include monitoring for unusual patterns in server logs that might indicate exploitation attempts. Security teams should conduct comprehensive vulnerability assessments to identify all instances of affected GoAhead versions within their infrastructure and prioritize remediation efforts based on risk exposure. Network segmentation and intrusion detection systems can provide additional layers of protection by monitoring for the specific malformed header patterns associated with this vulnerability.