Executive brief
A classic networking vulnerability, known as a 'Land' attack, affects various operating systems and networking devices. An attacker can send a specially crafted network packet that causes a system to attempt to communicate with itself, leading to a crash or severe performance slowdown. This results in a denial of service, preventing legitimate users from accessing the affected system or its services.
Technical details
The 'Land' attack is a classic denial of service (DoS) vulnerability involving the transmission of a spoofed TCP SYN packet where the source IP address and port are set to be identical to the destination IP address and port. When a vulnerable TCP/IP stack receives such a packet, it may enter an infinite loop or crash while attempting to respond to itself. This is a remote, unauthenticated attack vector. While modern operating systems have long since patched this issue, it historically affected a wide range of platforms including HP-UX and various networking appliances. Mitigation typically involves ingress filtering to drop packets with internal source addresses arriving from external interfaces.
Affected products
- HP HP-UX
- NetApp ONTAP
Timeline
- 1997-12-01: disclosed: Initial publication date
- 2017-08-15: advisory: NetApp advisory published