CVE-2018-18541 in Teeworlds
Summary
by MITRE
In Teeworlds before 0.6.5, connection packets could be forged. There was no challenge-response involved in the connection build up. A remote attacker could send connection packets from a spoofed IP address and occupy all server slots, or even use them for a reflection attack using map download packets.
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Analysis
by VulDB Data Team • 05/30/2023
The vulnerability identified as CVE-2018-18541 affects the Teeworlds multiplayer gaming platform prior to version 0.6.5, representing a critical authentication flaw that undermines the fundamental security of the network connection process. This weakness stems from the complete absence of challenge-response mechanisms during the connection establishment phase, creating an environment where malicious actors can exploit the protocol's inherent design flaws to manipulate server resources. The vulnerability resides in the core network protocol implementation where connection packets lack any form of cryptographic verification or authentication tokens that would normally validate the legitimacy of incoming connection attempts.
The technical nature of this flaw allows attackers to forge connection packets without proper authentication, effectively bypassing the normal connection validation procedures that should occur between client and server. This absence of challenge-response validation creates a pathway for remote exploitation where threat actors can craft and transmit connection packets from spoofed ip addresses, completely circumventing the normal connection flow that would typically require proof of address ownership or other authentication mechanisms. The vulnerability specifically impacts the initial handshake process where clients attempt to establish connections with game servers, leaving the system vulnerable to both resource exhaustion and amplification attacks.
Operationally, this vulnerability enables attackers to execute several damaging scenarios including server slot exhaustion attacks where malicious actors can consume all available server connection slots by sending forged connection packets from various spoofed addresses. The impact extends beyond simple resource depletion to include potential reflection attacks where attackers can leverage the forged connection packets to direct map download traffic toward victim systems, amplifying the attack traffic volume. This creates a significant operational risk for game servers that may experience service degradation or complete unavailability due to legitimate connection attempts being overwhelmed by forged packets, while also potentially being used as launch points for broader network attacks.
The weakness aligns with CWE-347, which addresses improper certificate validation and authentication flaws in network protocols, and demonstrates characteristics consistent with attack patterns found in the MITRE ATT&CK framework under the initial access and privilege escalation domains. The vulnerability's exploitation requires minimal technical expertise while providing substantial impact potential, making it particularly dangerous in multi-user gaming environments where server resources are limited and connection slots are finite. Organizations running Teeworlds servers should prioritize immediate patching to version 0.6.5 or later, while implementing network-level mitigations such as rate limiting and ip address filtering to prevent exploitation. Additionally, administrators should consider implementing connection rate limiting at the network level and monitoring for unusual connection patterns that may indicate spoofed packet activity, as the vulnerability fundamentally undermines the security assumptions of the underlying network protocol.