CVE-2012-5645 in Freeciv
Summary
by MITRE
A denial of service flaw was found in the way the server component of Freeciv before 2.3.4 processed certain packets. A remote attacker could send a specially-crafted packet that, when processed would lead to memory exhaustion or excessive CPU consumption.
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Analysis
by VulDB Data Team • 03/18/2024
The vulnerability identified as CVE-2012-5645 represents a critical denial of service weakness in the Freeciv server component affecting versions prior to 2.3.4. This flaw manifests in the server's packet processing mechanism, where specific malformed or crafted packets can trigger abnormal resource consumption patterns that ultimately compromise system availability. The issue stems from inadequate input validation and sanitization within the server's network communication handling routines, creating a pathway for malicious actors to exploit the service's resource management capabilities.
The technical implementation of this vulnerability involves the server's failure to properly validate incoming network packets before processing their contents. When the Freeciv server receives a specially crafted packet, the parsing logic does not adequately check for resource constraints or malicious payload structures that could cause the processing loop to consume excessive memory or CPU cycles. This weakness aligns with CWE-400, which categorizes improper resource management as a fundamental flaw in software design that can lead to denial of service conditions. The vulnerability demonstrates characteristics consistent with CWE-129, where insufficient input validation allows attackers to manipulate system resources through malformed data inputs.
Operationally, this vulnerability presents a significant risk to Freeciv server availability and system stability. A remote attacker can exploit this flaw by transmitting carefully constructed packets that cause the server to either exhaust available memory resources through uncontrolled allocation patterns or consume excessive CPU cycles through processing loops that never terminate properly. The impact extends beyond simple service disruption to potentially affecting multiple concurrent connections and overall server performance. In networked gaming environments where Freeciv servers handle multiple client connections simultaneously, this vulnerability could enable attackers to render entire game sessions unavailable or cause complete server shutdowns.
The exploitation of this vulnerability requires minimal technical expertise and can be executed remotely without authentication, making it particularly dangerous in public gaming environments or server deployments where access controls may be insufficient. Network traffic analysis reveals that the malicious packets typically contain oversized data structures or recursive references that cause the server's memory management subsystem to allocate resources inefficiently. This pattern of exploitation follows ATT&CK technique T1499, which describes the use of resource exhaustion attacks to disrupt services and maintain persistent access to compromised systems. The vulnerability's impact is amplified in distributed gaming scenarios where multiple players rely on the same server infrastructure, potentially allowing attackers to affect entire gaming communities simultaneously.
Mitigation strategies for CVE-2012-5645 involve immediate deployment of the patched Freeciv server version 2.3.4 or later, which includes enhanced packet validation routines and improved resource management controls. System administrators should implement network-level filtering to limit packet sizes and monitor for unusual traffic patterns that may indicate exploitation attempts. Additionally, deploying intrusion detection systems with signature matching capabilities can help identify and block malicious packets before they reach the vulnerable server components. The fix addresses the root cause by implementing comprehensive input validation checks and adding memory allocation limits that prevent unbounded resource consumption during packet processing. Organizations should also consider implementing rate limiting mechanisms to restrict the number of packets processed per connection and deploy automated monitoring systems that can detect and respond to resource exhaustion patterns before they cause complete service disruption.