ZyXEL Communications 200 Series - Manual (Page 494)

Chapter 29 IDP
ZyWALL USG 100/200 Series User’s Guide
494
29.6.3 IDP Service Groups
An IDP service group is a set of related packet inspection signatures.
DoS/DDoS The goal of Denial of Service (DoS) attacks is not to steal information, but to
disable a device or network on the Internet.
A distributed denial-of-service (DDoS) attack is one in which multiple
compromised systems attack a single target, thereby causing denial of service
for users of the targeted system.
Scan A scan describes the action of searching a network for an exposed service. An
attack may then occur once a vulnerability has been found. Scans occur on
several network levels.
A network scan occurs at layer-3. For example, an attacker looks for network
devices such as a router or server running in an IP network.
A scan on a protocol is commonly referred to as a layer-4 scan. For example,
once an attacker has found a live end system, he looks for open ports.
A scan on a service is commonly referred to a layer-7 scan. For example, once
an attacker has found an open port, say port 80 on a server, he determines that
it is a HTTP service run by some web server application. He then uses a web
vulnerability scanner (for example, Nikto) to look for documented vulnerabilities.
Buffer Overflow A buffer overflow occurs when a program or process tries to store more data in
a buffer (temporary data storage area) than it was intended to hold. The excess
information can overflow into adjacent buffers, corrupting or overwriting the
valid data held in them.
Intruders could run codes in the overflow buffer region to obtain control of the
system, install a backdoor or use the victim to launch attacks on other devices.
Virus/Worm A computer virus is a small program designed to corrupt and/or alter the
operation of other legitimate programs. A worm is a program that is designed to
copy itself from one computer to another on a network. A worm’s uncontrolled
replication consumes system resources, thus slowing or stopping other tasks.
Backdoor/Trojan A backdoor (also called a trapdoor) is hidden software or a hardware
mechanism that can be triggered to gain access to a program, online service or
an entire computer system. A Trojan horse is a harmful program that is hidden
inside apparently harmless programs or data.
Although a virus, a worm and a Trojan are different types of attacks, they can be
blended into one attack. For example, W32/Blaster and W32/Sasser are
blended attacks that feature a combination of a worm and a Trojan.
Access Control Access control refers to procedures and controls that limit or detect access.
Access control attacks try to bypass validation checks in order to access
network resources such as servers, directories, and files.
Web Attack Web attacks refer to attacks on web servers such as IIS (Internet Information
Services).
Table 157 Policy Types (continued)
POLICY TYPE DESCRIPTION
Table 158 IDP Service Groups
WEB_PHP WEB_MISC WEB_IIS WEB_FRONTPAGE
WEB_CGI WEB_ATTACKS TFTP TELNET
SQL SNMP SMTP RSERVICES
RPC POP3 POP2 P2P
ORACLE NNTP NETBIOS MYSQL
MISC_EXPLOIT MISC_DDOS MISC_BACKDOOR MISC