CVE-2019-3804 in Cockpit
Summary
by MITRE
It was found that cockpit before version 184 used glib's base64 decode functionality incorrectly resulting in a denial of service attack. An unauthenticated attacker could send a specially crafted request with an invalid base64-encoded cookie which could cause the web service to crash.
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Analysis
by VulDB Data Team • 08/08/2023
The vulnerability CVE-2019-3804 affects the Cockpit web-based system administration tool, specifically versions prior to 184. This issue represents a denial of service vulnerability that stems from improper handling of base64-encoded data within the application's authentication mechanism. The flaw exists in how Cockpit processes cookies containing base64-encoded values, creating a potential attack vector that could disrupt service availability for legitimate users. The vulnerability impacts the core web service functionality, making it a critical concern for system administrators who rely on Cockpit for remote management operations.
The technical root cause of this vulnerability lies in Cockpit's incorrect implementation of glib's base64 decoding functionality. When processing authentication cookies, the application fails to properly validate or handle malformed base64 input, leading to unexpected behavior during the decoding process. This improper error handling creates a condition where specially crafted invalid base64-encoded requests can trigger an application crash. The vulnerability specifically targets the web service layer where authentication cookies are processed, making it accessible to unauthenticated attackers who can exploit the flaw without requiring any prior access credentials. This type of vulnerability falls under the category of improper input validation and can be classified as CWE-20, which represents "Improper Input Validation" in the Common Weakness Enumeration framework.
The operational impact of CVE-2019-3804 extends beyond simple service disruption, as it can effectively render the Cockpit management interface unavailable to authorized users. An attacker exploiting this vulnerability can cause the web service to crash repeatedly, potentially leading to extended downtime for system administration tasks. This denial of service condition affects not only the immediate availability of the management interface but can also impact the overall system monitoring and maintenance capabilities. The vulnerability's accessibility to unauthenticated attackers means that any system running vulnerable versions of Cockpit is at risk, regardless of network segmentation or access controls. This makes it particularly dangerous in environments where Cockpit is exposed to untrusted networks or where security boundaries are not properly enforced.
Mitigation strategies for this vulnerability primarily involve upgrading to Cockpit version 184 or later, which contains the necessary patches to properly handle base64-encoded cookie data. System administrators should prioritize this update across all affected systems and implement proper monitoring to detect potential exploitation attempts. Additional defensive measures include implementing rate limiting on authentication requests, configuring web application firewalls to detect and block malformed base64-encoded data patterns, and establishing robust log monitoring for unusual crash patterns. Organizations should also consider implementing network segmentation to limit exposure of Cockpit services to untrusted networks. From an ATT&CK perspective, this vulnerability aligns with techniques related to service disruption and denial of service, specifically targeting the web application layer where authentication mechanisms are implemented. The vulnerability demonstrates how seemingly minor implementation flaws in standard library functions can create significant security risks when proper input validation and error handling are not implemented.