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Hello, everyone.
Windows Server 2003 and XP SP2 (with Windows Firewall turned off) are vulnerable to LAND
attack.
LAND attack:
Sending TCP packet with SYN flag set, source and destination IP address and source and
destination port as of destination machine, results in 15-30 seconds DoS condition.
Tools used:
IP Sorcery for creating malicious packet, Ethereal for sniffing it and tcpreplay for
replaying.
Results:
Sending single LAND packet to file server causes Windows explorer freezing on all
workstations currently connected to the server. CPU on server goes 100%. Network monitor on
the victim server sometimes can not even sniff malicious packet. Using tcpreplay to script
this attack results in total collapse of the network.
Vulnerable operating systems:
Windows 2003
XP SP2
other OS not tested (I have other things to do currently – like checking firewalls on my
networks ;) )
Solution:
Use Windows Firewall on workstations, use some firewall capable of detecting LAND attacks
in front of your servers.
Ethic:
Microsoft was informed 7 days ago (25.02.2005, GMT +1, local time), NO answer received, so
I decided to share this info with security community.
Dejan Levaja
System Engineer
Bulevar JNA 251
11000 Belgrade
Serbia and Montenegro
cell: +381.64.36.00.468
email: dejan@levaja.com
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