CVE-2002-1159 in Canna
Summary
by MITRE
Canna 3.6 and earlier does not properly validate requests, which allows remote attackers to cause a denial of service or information leak.
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Analysis
by VulDB Data Team • 05/29/2019
The vulnerability identified as CVE-2002-1159 affects Canna 3.6 and earlier versions of the Canna input method system, which is a Japanese input method framework commonly used in Unix-like operating systems. This flaw represents a critical security issue that stems from inadequate request validation mechanisms within the software's communication protocols. The vulnerability exists in the way Canna handles incoming requests from remote clients, failing to properly sanitize or validate the data structures and parameters that are transmitted through its network interfaces.
The technical flaw manifests as a lack of proper input validation that allows malicious actors to craft specially malformed requests that exploit weaknesses in the Canna daemon's processing logic. When the system receives these malformed requests, it fails to properly handle the unexpected data, leading to potential system instability and resource exhaustion. The vulnerability specifically impacts the network communication layer where Canna listens for client connections and processes input method requests. This type of vulnerability falls under the CWE-20 category, which represents "Improper Input Validation," and represents a classic example of how insufficient validation can lead to system compromise.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can potentially enable information leakage from the affected system. Remote attackers who successfully exploit this vulnerability can cause the Canna service to crash or behave unpredictably, resulting in service disruption for legitimate users who rely on Japanese input capabilities. Additionally, the information leak aspect suggests that attackers might be able to extract sensitive data from memory or system resources that are not properly protected from unauthorized access. This vulnerability is particularly concerning in multi-user environments where Canna serves as a shared input method service, as it could allow attackers to gain unauthorized access to system information or disrupt service availability for multiple users simultaneously.
The attack surface for this vulnerability is primarily through network-based exploitation, as Canna typically operates as a network service that accepts remote connections from client applications. Attackers would need to be able to establish network connectivity to the Canna service port to exploit this weakness, which typically operates on standard network ports used by input method daemons. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1499 which covers network denial of service attacks, and potentially T1566 which covers spearphishing with social engineering. Organizations using Canna should consider implementing network segmentation and access controls to limit exposure, while also ensuring that the service is only accessible from trusted network segments. The vulnerability demonstrates the importance of proper input validation in network services and highlights why security-conscious development practices should always include comprehensive validation of all external inputs to prevent exploitation through malformed data. System administrators should prioritize patching affected systems and monitoring for potential exploitation attempts, while also implementing intrusion detection systems that can identify unusual network traffic patterns associated with denial of service attacks against input method services.