Denial-of-Service (DoS) 665
Lab 95: Denial-of-Service ??“??“ Trash2.c
Create Denial-of-Service Traffic: Trash2.c
Prerequisites: None
Countermeasures: Secure ACLs, Bastion servers/workstations, ingress
filtering
Description: Trash2.c sends random, spoofed, ICMP/IGMP packets with
a random spoof source, causing the target to either lock up or raise
the CPU use on the target, effectively creating a DoS.
Procedure: Compile, set the parameters, and execute against the target.
Retrieve the target IP address by typing ipconfig and pressing Enter.
666 Practical Hacking Techniques and Countermeasures
Start the Ethereal application on the target as outlined in Lab 41. From the
directory on the attacking machine containing the Trash2.c file, type:
gcc trash2.c ??“o trash2
The Trash2 executable will be created.
Denial-of-Service (DoS) 667
To execute Trash2 use the following syntax:
./trash2
Trash2 will begin to send the identified number of packets to the target.
668 Practical Hacking Techniques and Countermeasures
From the target machine click Ethereal??™s Stop button.
Ethereal will display the packets captured.
Denial-of-Service (DoS) 669
Click on the Source column to sort the packets based on Source address.
(You may have to click it twice.)
Observe that the target received a massive amount (10,000) of fragmented
IP packets. Also notice that if you expand the center area of Ethereal and look
at the contents of the packets, the Ethernet II information displays the actual
IP address of the sender whereas the Internet Protocol displays the
???spoofed??? source IP address.
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