when an attacker attempts to gain entry into or disrupt the normal operations of an information system, almost always with the intent to do harm
consists of procedures and systems created and operated to detect system intrusions
What is Intrusion detection?
encompasses actions an organization undertakes when intrusion event is detected
What is Intrusion reaction?
1- finalize restoration of operations to a normal state
2- Detect a violation of its configuration and activate alarm
3- Many IDSs enable administrators to configure systems to notify them directly of trouble via e-mail or pagers
4- Systems can also be configured to notify an external security service organization of a "break-in"
What does Intrusion correction do?
Site policy awareness
True attack stimulus
Alarm clustering and compaction
Alert or alarm
False attack stimulus
False negative and false positive
- Prevent problem behaviors by increasing the perceived risk of discovery and punishment
- Detect attacks and other security violations
- Detect and deal with preambles to attacks
- Document existing threat to an organization
- Act as quality control for security design and administration, especially of large and complex enterprises
- Provide useful information about intrusions that take place
Why Use an IDPS?
Examines traffic flow on a network in an attempt to recognize abnormal patterns
Installed at specific place in the network where it can watch traffic going into and out of particular network segment
How does Network-based IDPS work:
detects an attack by using special implementation of TCP/IP stack:
In process of protocol stack verification, NIDPSs look for invalid data packets
In application protocol verification, higher-order protocols are examined for unexpected packet behavior or improper use
How does NIDPS signature matching work?
- Good network design and placement of NIDPS can enable organization to use a few devices to monitor large network
- NIDPSs are usually passive and can be deployed into existing networks with little disruption to normal network operations
- NIDPSs not usually susceptible to direct attack and may not be detectable by attackers
What are the Advantages of NIDPSs?
- Can become overwhelmed by network volume and fail to recognize attacks
- Require access to all traffic to be monitored
- Cannot analyze encrypted packets
- Cannot reliably ascertain if attack was successful or not
- Some forms of attack are not easily discerned by NIDPSs, specifically those involving fragmented packets
What are the Disadvantages of NIDPSs?
Monitors and analyzes wireless network traffic
Issues associated with it include physical security, sensor range, access point and wireless switch locations, wired network connections, cost
How does a Wireless NIDPS work?
It examines network traffic in order to identify problems related to the flow of traffic
Types of events commonly detected include DoS attacks, scanning, worms, unexpected application services, policy violations.
How does a Network behavior analysis system work?
Resides on a particular computer or server and monitors activity only on that system
Benchmark and monitor the status of key system files and detect when intruder creates, modifies, or deletes files
Most HIDPSs work on the principle of configuration or change management
What is a Host-based IDPS?
can usually be installed so that it can access information encrypted when traveling over network
What is the advantage of Host-Based over Network IDPS's
Pose more management issues
Vulnerable both to direct attacks and attacks against host operating system
Does not detect multi-host scanning, nor scanning of non-host network devices
Susceptible to some denial-of-service attacks
Can use large amounts of disk space
Can inflict a performance overhead on its host systems
Disadvantages of HIDPSs
Examine data traffic in search of patterns that match known signatures because many attacks have clear and distinct signatures
What is a Signature-based IDPS?
(stat IDPS) or behavior-based IDPS, sample network activity to compare to traffic that is known to be normal the IDPS will trigger an alert
Requires much more overhead and processing capacity than signature-based
May generate many false positives
How do Statistical anomaly-based IDPS's work?
NIST 800-94 states defines a SPA as a process of comparing predetermined profiles of definitions of benign activity for each protocol state against observed events to identify deviations
Stores and uses relevant data detected in a session to identify intrusions involving multiple requests/responses; allows IDPS to better detect specialized, multisession attacks
Drawbacks: analytical complexity; processing overhead; may fail to detect unless protocol violates fundamental behavior; may cause problems with protocol it's examining
Stateful protocol analysis IDPS
Log file monitor (LFM) similar to NIDPS
Reviews log files generated by servers, network devices, and even other IDPSs for patterns and signatures
Patterns that signify attack may be much easier to identify when entire network and its systems are viewed holistically
Requires allocation of considerable resources since it will involve the collection, movement, storage, and analysis of large quantities of log data
How do Log file monitors work?
Active response: collecting additional information about the intrusion, modifying the network environment, taking action against the intrusion
Passive response: setting off alarms or notifications, collecting passive data through SNMP traps
Once IDPS detects an anomalous network situation what are the options?
- Monitoring and analysis of system events and user behaviors
- Testing security states of system configurations
- Baselining security state of system and tracking changes
- Recognizing system event patterns matching known attacks
- Recognizing activity patterns that vary from normal activity
- Managing OS audit and logging mechanisms and data they generate
- Alerting appropriate staff when attacks are detected
- Measuring enforcement of security policies encoded in analysis engine
- Providing default information security policies
- Allowing non-security experts to perform important security monitoring functions
IDPSs perform the following functions well
- Compensating for weak/missing security mechanisms in protection infrastructure
- Instantaneously detecting, reporting, responding to attack when there is heavy network or processing load
- Detecting new attacks or variants of existing attacks
- Effectively responding to attacks by sophisticated attackers
- Investigating attacks without human intervention
- Resisting attacks intended to defeat or circumvent them
- Compensating for problems with fidelity of data sources
- Dealing effectively with switched networks
IDPSs cannot perform the following functions
Centralized,Fully distributed,Partially distributed
An IDPS can be implemented via one of three basic control strategies
Location 1: Behind each external firewall, in the network DMZ
Location 2: Outside an external firewall
Location 3: On major network backbones
Location 4: On critical subnets
NIST recommends four locations for NIDPS sensors, name them.
2- blacklists and whitelists,
3- alert settings,
4- code viewing and editing
IDPSs are evaluated using four dominant metrics
decoy systems designed to lure potential attackers away from critical systems and encourage attacks against the themselves
What are Honeypots?
Divert attacker from accessing critical systems
Collect information about attacker's activity
Encourage attacker to stay on system long enough for administrators to document event and, perhaps, respond
Honeypots are designed to:
a honeypot that has been protected so it cannot be easily compromised such as with traditional IDPS's
What is a Padded cell?
When the IDS detects attackers, it seamlessly transfers them to a special simulated environment where they can cause no harm—the nature of this host environment is what gives approach to the name padded cell
How does Padded cell work?
- Attackers can be diverted to targets they cannot damage
- Administrators have time to decide how to respond to attacker
- Attackers' actions can be easily and more extensively monitored, and records can be used to refine threat models and improve system protections
- Honey pots may be effective at catching insiders who are snooping around a network
Advantages of Honeypots, Honeynets, and Padded Cell Systems
- Legal implications of using such devices are not well defined
- Honeypots and padded cells have not yet been shown to be generally useful security technologies
- Expert attacker, once diverted into a decoy system, may become angry and launch a more hostile attack against an organization's systems
- Administrators and security managers will need a high level of expertise to use these systems
disadvantages of Honeypots, Honeynets, and Padded Cell Systems
Use combination of techniques to detect an intrusion and trace it back to its source
What are Trap and Trace Systems
One tool (LaBrea) takes up unused IP address space to pretend to be a computer and allow attackers to complete a connection request, but then holds connection open
Give an example of Active Intrusion Prevention.
Typically used to collect information that attacker would need to launch successful attack
What do Scanning and Analysis Tools do?
Tools used by both attackers and defenders to identify computers active on a network and other useful information ,it can scan for specific types of computers, protocols, or resources, or their scans can be generic
What are Port Scanners?
Detecting a target computer's operating system (OS) is very valuable to an attacker
There are many tools that use networking protocols to determine a remote computer's OS
How would an Operating System Detection Tool work
Network tool that collects copies of packets from network and analyzes them
Can provide network administrator with valuable information for diagnosing and resolving networking issues
In the wrong hands, a sniffer can be used to eavesdrop on network traffic
To use packet sniffer legally, administrator must be on network that organization owns, be under direct authorization of owners of network, and have knowledge and consent of the content creators
Organization that spends its time securing wired network and leaves wireless networks to operate in any manner is opening itself up for security breach
Security professional must assess risk of wireless networks
A wireless security toolkit should include the ability to sniff wireless traffic, scan wireless hosts, and assess level of privacy or confidentiality afforded on the wireless network
Wireless Security Tools
Based on the use of some measurable human characteristic or trait to authenticate the identity of a proposed systems user (a supplicant)
Relies upon recognition
Includes fingerprint comparison, palm print comparison, hand geometry, facial recognition using a photographic id card or digital camera, retinal print, iris pattern
Characteristics considered truly unique: fingerprints, retina of the eye, iris of the eye
Biometric Access Control
False reject rate: the rejection of legitimate users
False accept rate: the acceptance of unknown users
Crossover error rate (CER): the point where false reject and false accept rates cross when graphed
Biometric technologies evaluated on three basic criteria:
detects violation of its configuration and activates alarm
What is an Intrusion detection system (IDPS)
honey nets, padded cell
Honey pots are decoy systems; two variations are known as _____ _____ and _______ _____ systems
pinpoint vulnerabilities in systems, holes in security components, and unsecured aspects of network
Scanning and analysis tools are used to:
Can detect local events on host systems and detect attacks that may elude a network-based IDPS
Functions on host system, where encrypted traffic will have been decrypted and is available for processing
Not affected by use of switched network protocols
Can detect inconsistencies in how applications and systems programs were used by examining records stored in audit logs
What are the advantages of an HIDPS?
as new attack strategies are identified, the IDPS's database of signatures must be continually updated
What is the disadvantage of a Signature-based IDPS?
all IDPS control functions are implemented and managed in a central location
What is the Centralized Control strategy
all control functions are applied at the physical location of each IDPS component
What is the Fully distributed Control strategy
Combines Centralized & Fully distributed control strategies.
What is the Partially distributed Control strategy
the process of attracting attention to system by placing tantalizing bits of information in key locations
Enticement is legal and ethical, entrapment is not
the action of luring an individual into committing a crime to get a conviction
Enticement is legal and ethical, entrapment is not
is series of steps or processes used by an attacker, in a logical sequence, to launch attack against a target system or network
What is an Attack protocol ?
the organized research of Internet addresses owned or controlled by a target organization
What is Footprinting?
systematic survey of all of target organization's Internet addresses collected during the footprinting phase
Fingerprinting reveals useful information about internal structure and operational nature of target system or network for anticipated attack
What is Fingerprinting
scan networks for highly detailed information; initiate traffic to determine holes
What do Active vulnerability scanners do?