CVE-2002-2243 in Akfingerd
Summary
by MITRE
Akfingerd 0.5 and possibly earlier versions only allows one connection at a time and does not time out connections, which allows remote attackers to cause a denial of service (refused connections) by opening a connection and not closing it.
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Analysis
by VulDB Data Team • 04/22/2019
The vulnerability described in CVE-2002-2243 affects Akfingerd version 0.5 and potentially earlier releases, representing a classic resource exhaustion flaw that can lead to denial of service conditions. This issue stems from the service's inability to handle concurrent connections properly and its lack of connection timeout mechanisms, creating an environment where malicious actors can exploit the system's limited capacity. The vulnerability specifically targets the daemon's connection handling logic, where it accepts incoming connections but fails to implement proper connection management protocols that would prevent indefinite connection maintenance.
From a technical perspective, the flaw manifests as a lack of connection limiting and timeout functionality within the Akfingerd service implementation. The service operates with a single-threaded connection model that processes one connection at a time, meaning that once a connection is established, it remains active indefinitely until manually terminated by the client. This behavior creates a resource depletion scenario where connection slots become unavailable for legitimate users, effectively preventing new connection attempts from succeeding. The absence of connection timeout mechanisms means that even if a client disconnects abnormally, the service continues to maintain the connection state, consuming system resources unnecessarily.
The operational impact of this vulnerability extends beyond simple service disruption, as it creates a persistent denial of service condition that can be maintained indefinitely without requiring significant resources from the attacker. Remote attackers can exploit this weakness by establishing a single connection to the service and then leaving it open without proper termination, causing subsequent legitimate connection attempts to fail with refused connections. This type of attack can be particularly damaging in environments where the service is critical for network operations or authentication functions, as it can effectively render the system unusable for authorized users. The vulnerability aligns with CWE-400, which categorizes resource exhaustion issues, and demonstrates how poor connection management can create systemic service availability problems.
The attack vector for this vulnerability is straightforward and requires minimal technical expertise to execute, making it particularly dangerous in production environments where such services may be exposed to untrusted networks. According to ATT&CK framework category T1499, this represents a resource exhaustion attack that specifically targets service availability by consuming connection resources. The vulnerability also reflects poor implementation practices related to connection lifecycle management, where the service fails to implement proper connection monitoring and cleanup mechanisms. Organizations affected by this vulnerability should consider implementing connection timeouts, connection limiting, and proper resource cleanup procedures as immediate mitigations. Additionally, network-level protections such as connection rate limiting and firewall rules can help reduce the impact of such attacks while more permanent solutions involve updating to patched versions of the service or implementing connection monitoring tools to detect and terminate stale connections automatically.