CVE-2012-5645: 
Freeciv vulnerability analysis and mitigation

CVE-2012-5645 is a denial of service vulnerability affecting the server component of Freeciv before version 2.3.4. The vulnerability was discovered in December 2012 and involves the way the server processes certain network packets. This flaw specifically relates to the processing of invalid packets with whole packet length lower than packet header size, which could lead to memory exhaustion (Openwall OSS).

The vulnerability exists in the packet processing mechanism of the Freeciv server component. When processing certain packets with invalid packet lengths (specifically where the whole packet length is lower than the packet header size), the server could be forced into a state leading to memory exhaustion. The issue was fixed in version 2.3.4 through a patch that implements sanity checks for packet length received over network against values less than header length alone (Debian Bug).

When exploited, this vulnerability could cause the Freeciv server to terminate due to memory exhaustion, resulting in a denial of service condition. This would affect the availability of the game server for all connected players (CVE Mitre).

The vulnerability can be exploited remotely by sending specially-crafted packets to the Freeciv server. An attacker could trigger the vulnerability by sending invalid packets with packet lengths lower than the packet header size (Openwall OSS).

The vulnerability was fixed in Freeciv version 2.3.4. Users should upgrade to this version or later to mitigate the issue. The fix implements proper sanity checks for packet lengths received over the network (Debian Bug).