IPS/IDS - SudeeraJ.com

Introduction Intrusion & current Threat scenario
Introduction to IDS/IPS
IDS/IPS Detection Techniques
Main Types of IDS/IPS
Introduction of UTM
Intrusion Detection with Tripwire
What is Intrusion?
• A set of actions aimed at compromising the
security goals (confidentiality, integrity, availability of a
computing/networking resource)
Why need to protect?
Current Threat Scenario
Malicious intent
Blended Threats
Identity theft
Data Corruption
Information Leak
Why need to protect? (Cont..)
• There are two types of threats
– External threats
– Internal threats
Why need to protect? (Cont..)
• External Threats (Targeting the Individuals)
Who are the attackers?
• It is no longer individuals
• Attacks executed as joint ventures among professional
programmers with access to greater pooled resources
• Consortiums dedicated to the creation and distribution of
malicious software intended to steal money from
Why need to protect? (Cont..)
What are the motives?
• To gain attention
• Financial theft (main driver of malware authors)
• Identity theft
Who are the victims?
• Small corporations
• Key Individuals
• Basically any one
Why need to protect? (Cont..)
• Internal Threats
– Insiders acting as initiators themselves or as conduits for
other attacks
– User Ignorance
– Malicious Intent - Intentional security breaches
– Disgruntled employees
Why need to protect? (Cont..)
• Why such Insider threats can lead to more
– Employees carry valid authorization and privacy of
the organization’s information
– Dishonest insiders’ can exploit an organization’s
 To commit identity fraud and expose confidential information
 For personal gain or organized crime
– Insider attacks can be more difficult to detect than
external penetration attempts
How to protect?
There are two ways of protection mechanisms
• Intrusion detection (IDS)
• Intrusion prevention (IPS)
Introduction to IDS
• Intrusion detection system (IDS)
– A system that automatically identifying and
responding to intrusion activities
Introduction to IPS
• Intrusion prevention system (IPS)
– A system that has an ambition to both detect
intrusions and manage responsive actions
Introduction to IPS (Cont..)
– Technically, an IPS contains an IDS and
combines it with preventive measures
– IPS use IDS algorithms to monitor and drop/allow
traffic based on expert analysis
– The ”firewall” part of an IPS can prevent malicious
traffic from entering/exiting the network
Basic assumptions for IDS/IPS
• Basic assumptions:
– System activities are observable
– Normal and intrusive activities have distinct evidence
– The goal of an IDS/IPS is to detect the difference
How IDS/IPS Works?
• The IPS monitors the network much like the IDS
but when an event occurs, it takes action based
on prescribed rules
• Security administrator can define such rules so
the systems respond in the way they would
How IDS/IPS Works? (Cont..)
How IDS/IPS Works? (Cont..)
• IPS can be achieved through three main
– Building systems with no vulnerability
– Taking perfect remediation steps to uncover
vulnerabilities and patch them
– Detecting the exploit attempts and blocking them
before serious damage is done
How IDS/IPS Protects?
• IPS technologies can respond to a detected
threat by attempting to prevent it from
succeeding. They use several response
techniques, which can be divided into the
following groups
– The IPS stops the attack itself
– The IPS changes the security environment
– The IPS changes the attack’s content
How IDS/IPS Protects?(Cont..)
• The IPS stops the attack itself
– Terminate the network connection or user session
that is being used for the attack
– Block access to the target from the offending user
account, IP address, or other attacker attribute. Block
all access to the targeted host, service, application, or
other resource
How IDS/IPS Protects?(Cont..)
• The IPS changes the security environment
– The IPS could change the configuration of other
security controls to disrupt an attack
– Common examples are reconfiguring a network
device such as firewall, router, and switch to block
access from the attacker
How IDS/IPS Protects?(Cont..)
• The IPS changes the attack’s content
– IPS technologies can remove or replace malicious
portions of an attack to make it benign
 An example is an IPS that acts as a proxy and
normalizes incoming requests and permitting the
cleaned data to reach its recipient
How IDS/IPS detects?
There are different types of approaches is
used in the IPS to secure the network
– Signature-Based
– Anomaly-Based
– Policy-Based
– Protocol-Analysis-Based
These approaches are also used to classify IDS/IPS
systems and the classification is called IDS/IPS by
Detection Model
How IDS/IPS detects? (Cont...)
• Signature-Based IPS
– It is the commonly used by many IPS solutions
– Signatures are added to the devices that identify a
pattern that the most common attacks present
– That’s why it is also known as pattern matching
– These signatures can be added, tuned, and updated
to deal with the new attacks
How IDS/IPS detects? (Cont...)
• Policy-based IPS
– It is more concerned with enforcing the security
policy of the organization
– Alarms are triggered if activities are detected that
violate the security policy coded by the organization
– With this type approaches security policy is written
into the IPS device
How IDS/IPS detects? (Cont...)
• Anomaly-Based approach IPS
– It is also called as profile-based
– It attempts to discover activity that deviates from
what an engineer defines as normal activity
– Anomaly-based approach can be statistical anomaly
detection and non-statistical anomaly detection
– The statistical approach is about the traffic patterns
on the network itself, and the non-statistical method
is about information coded by the solution vendor
How IDS/IPS detects?(Cont...)
• Protocol-analysis-based IPS
– It is similar to signature based approach
– Most signatures examines common settings, but the
protocol-analysis-based approach can do much
deeper packet inspection and is more flexible in
finding some types of attacks
IDS/IPS Detection Techniques
• Stateless
– Most of the network-based IDS currently available
are stateless. They typically monitor and analyze all
traffic in real-time on a packet-by-packet basis against
a database of known patters for a match
• State full
– A State-full IDS can be defined as a packet filtering
and analysis mechanism which makes decision on
current packet AND information from previous
IDS/IPS Detection Techniques
• Deep Packet Inspection
– Deep Packet Inspection mostly used in NIDS to look
within the application payload of a packet or traffic
stream and make decisions on the significance of that
data based on the content of that data (analyze the
packet header fields
– DPI technology can be effective against buffer
overflow attacks, denial of service (DoS) attacks,
sophisticated intrusions, and a small percentage of
worms that fit within a single packet
Main Types of IDS/IPS
• Scope based IPS protection (or by location)
– Host-Based Intrusion Prevention System (HIPS)
– Network-Based Intrusion Prevention System (NIPS)
Host Based IDS/IPS
• Host-based IPS is a software program that resides on
individual systems such as servers, workstations or
• Traffic flowing into or out of that particular system is
inspected and the behaviour of the applications and
operating system may be examined for indications of
an attack
• These host system-specific programs or agents may
protect just the operating system, or applications
running on the host as well as web servers
Host Based IDS/IPS (Cont..)
• When an attack is detected, the Host IPS software either
blocks the attack at the network Interface level, or issues
commands to the application or operating system to stop
the behaviour initiated by the attack
• It binds closely with the operating system kernel and
services, monitoring and intercepting system calls to the
kernel or APIs in order to prevent attacks as well as log
• One potential disadvantage with this approach is that,
given the necessarily tight integration with the host
operating system, future operating system upgrades could
cause problems
Benefits of Host IDS/IPS
• Protects mobile systems from attack when attached
outside the protected network
• Prevents internal attack or misuse on devices
located on the same network segment, Network IPS
only provides protection for data moving between
different segments
• Protects against encrypted attacks where the
encrypted data stream terminates at the system
being protected
Network Based IDS/IPS
• Network-Based Intrusion Prevention System
(NIPS) is software or dedicated hardware system
that connects directly to a network segment and
protects all of the systems attached to the same
or downstream network segments
Network Based IDS/IPS (Cont..)
• NIPS has at least two network interfaces,
one designated as internal and one as external
• As packets appear at the either interface they are
passed to the detection engine, at which point
the IPS device functions much as any IDS would
in determining whether or not the packet being
examined poses a threat
Benefits of Network IDS/IPS
• Easy deployment as a single sensor can protect
hundreds on systems
• A single control point for traffic can protect
thousands of systems located down stream of
the device (no matter what the operating system
or application)
• Protects against network DoS, DDos attacks and
SYN flood etc
Introduction of UTM
• Unified threat management (UTM) refers to a
comprehensive security product that includes
protection against multiple threats
• A UTM product typically includes a firewall,
antivirus software, content filtering and a spam
filter in a single integrated package
Advantages of UTM
• Simplicity
• Streamlined installation and use
• Ability to update all the security functions or
programs concurrently
• Eliminates the need for systems administrators to
maintain multiple security programs over time
Disadvantages of UTM
• UTM introduces a single point of failure it lead
for all the network security elements
• There is always a possibility of performance
constraint as there are limitations in hardware
processing capabilities to handle so many
applications/users simultaneously
• There is always challenge from cloud computing
initiatives and UTM’s might have to be deployed
in a virtual manner
Intrusion Detection with Tripwire
• Tripwire compares files and directories
against a baseline database of file locations,
dates modified, and other data
• It generates the baseline by taking a snapshot of
specified files and directories in a known secure
• After creating the baseline database, Tripwire
compares the current system to the baseline and
reports any modifications, additions, or deletions
Tripwire Architecture
Tripwire Commands
• twinstall.sh - Run the configuration script
• tripwire –init - The /var/lib/tripwire directory
contains the Tripwire database of your system's
files (*.twd) and a report directory where
Tripwire reports are stored
• tripwire –check - To run an integrity check
Tripwire compares the current, actual file system
objects with their properties as recorded in its
database. Violations are printed to standard
Tripwire Sample Report
• Due to the dynamic nature of network intrusion threats,
deploying a mixture of both technologies (HIPS & NIPS)
will provide the greatest level of protection for critical
• http://www.symantec.com/connect/articles/evolution-intrusiondetection-systems
• http://searchmidmarketsecurity.techtarget.com/sDefinition/0,,sid
• http://searchmidmarketsecurity.techtarget.com/sDefinition/0,,sid
• http://www.hig.no/index.php/content/download/8588/118736/fi
• http://searchsecurity.techtarget.com/tip/0,289483,sid14_gci1092
• http://idstutorial.com/anomaly-detection.php

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