CVE-2025-24356

 

fastd is a VPN daemon which tunnels IP packets and Ethernet frames over UDP. When receiving a data packet from an unknown IP address/port combination, fastd will assume that one of its connected peers has moved to a new address and initiate a reconnect by sending a handshake packet. This "fast reconnect" avoids having to wait for a session timeout (up to ~90s) until a new connection is established. Even a 1-byte UDP packet just containing the fastd packet type header can trigger a much larger handshake packet (~150 bytes of UDP payload). Including IPv4 and UDP headers, the resulting amplification factor is roughly 12-13. By sending data packets with a spoofed source address to fastd instances reachable on the internet, this amplification of UDP traffic might be used to facilitate a Distributed Denial of Service attack. This vulnerability is fixed in v23.
https://nvd.nist.gov/vuln/detail/CVE-2025-24356

Categories

CWE-405 : Asymmetric Resource Consumption (Amplification)
This can lead to poor performance due to "amplification" of resource consumption, typically in a non-linear fashion. This situation is worsened if the product allows malicious users or attackers to consume more resources than their access level permits.

References


 

CPE

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REMEDIATION




EXPLOITS


Exploit-db.com

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Other Nist (github, ...)

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CAPEC


Common Attack Pattern Enumerations and Classifications

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