CVE-2009-2732 in ntop
Summary
by MITRE
The checkHTTPpassword function in http.c in ntop 3.3.10 and earlier allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an Authorization HTTP header that lacks a : (colon) character in the base64-decoded string.
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Analysis
by VulDB Data Team • 12/15/2024
The vulnerability identified as CVE-2009-2732 affects ntop version 3.3.10 and earlier, specifically targeting the checkHTTPpassword function within the http.c module. This flaw represents a classic denial of service condition that can be exploited by remote attackers to crash the ntop daemon. The vulnerability stems from inadequate input validation within the HTTP authentication handling mechanism, where the system fails to properly process Authorization headers that do not contain the expected colon character in their base64-decoded format.
The technical implementation of this vulnerability occurs when the ntop daemon receives an HTTP Authorization header that contains base64-encoded credentials without a colon separator character. During the authentication process, the checkHTTPpassword function attempts to parse the decoded credentials string expecting a specific format where the username and password are separated by a colon. When this colon character is absent, the function proceeds to dereference a NULL pointer, leading to an immediate crash of the daemon process. This type of NULL pointer dereference falls under CWE-476 which specifically addresses the use of NULL pointers in software implementations.
From an operational perspective, this vulnerability presents a significant risk to network monitoring systems that rely on ntop for traffic analysis and security monitoring. The remote exploitation capability means that attackers can potentially disrupt network operations without requiring local access or authentication credentials. The daemon crash results in complete service interruption, forcing network administrators to restart the monitoring service and potentially losing valuable network traffic data during the downtime. This vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks targeting services and infrastructure.
The impact extends beyond simple service disruption as network monitoring systems are often critical infrastructure components that provide visibility into network traffic patterns and potential security incidents. When the ntop daemon crashes, it removes the ability to monitor network activity, creating a window of opportunity for attackers to conduct malicious activities without detection. The vulnerability demonstrates poor error handling practices and inadequate input validation that could be exploited in combination with other attacks to compromise network security monitoring capabilities. Organizations using affected versions of ntop should implement immediate mitigation strategies including updating to patched versions, implementing network segmentation to limit exposure, and monitoring for exploitation attempts. The vulnerability also highlights the importance of proper input validation and error handling in authentication mechanisms, particularly in network services that operate in untrusted environments where attackers may attempt to inject malformed data to trigger system failures.