Beginner's Guide to SIEM

Or: “Everything You Wanted to Know About Log Management
But were Afraid to Ask”
WWW.ALIENVAULT.COM
SIEM FOR BEGINNERS

A ROSE BY ANY OTHER NAME:
SLM/LMS, SIM, SEM,SEC, SIEM
Although the industry has settled on the term „SIEM‟ as the catch-all term for this type
of security software, it evolved from several different (but complementary) technologies
before it.
LMS - “Log Management System” – a system that collects and store Log Files (from Operating
Systems, Applications, etc) from multiple hosts and systems into a single location, allowing centralized
access to logs instead of accessing them from each system individually.
SLM /SEM– “Security Log/Event Management” – an LMS, but marketed towards security analysts
instead of system administrators. SEM is about highlighting log entries as more significant to security
than others.
SIM – “Security Information Management” - an Asset Management system, but with features to
incorporate security information too. Hosts may have vulnerability reports listed in their
summaries, Intrusion Detection and AntiVirus alerts may be shown mapped to the systems involved.
SEC - “Security Event Correlation” – To a particular piece of software, three failed login attempts to
the same user account from three different clients, are just three lines in their logfile. To an analyst, that
is a peculiar sequence of events worthy of investigation, and Log Correlation (looking for patterns in log
files) is a way to raise alerts when these things happen.
SIEM – “Security Information and Event Management” – SIEM is the “All of the Above” option, and
as the above technologies become merged into single products, became the generalized term for
managing information generated from security controls and infrastructure. We‟ll use the term SIEM for
the rest of this presentation.

Q: WHAT’S IN THE LOGS? WHAT’S IN THE LOGS?!!
A: The Information you need to answer “Who’s attacking us today?” and “How did they
get access to all our corporate secrets?
We may think of Security Controls as containing all the information we need to do security, but
often they only contain the things they have detected – there is no „before and after the event‟
context within them.
This context is usually vital to separate the false positive from true detection, the actual attack
from merely a misconfigured system.
Successful attacks on computer systems rarely look like real attacks except in hindsight – if this
were not the case, we could automate ALL security defenses without ever needing to employ
human analysts.
Attackers will try to remove and falsify log entries to cover their tracks – having a source of log
information that can be trusted is vital to any legal proceeding from computer misuse.

THE BLIND MEN AND THE SECURITY INFORMATION ELEPHANT
SIEM is about looking at what‟s happening on your network through a larger lens
than can be provided via any one security control or information source.
Your Intrusion Detection only understands Packets, Protocols and IP Addresses
Your Endpoint Security sees files, usernames and hosts
Your Service Logs show user logins, service activity and configuration changes.
Your Asset Management system sees apps, business processes and owners
None of these by themselves, can tell you what is happening to *your business* in
terms of securing the continuity of your business processes – but together, they
can…

SIEM: A SINGLE VIEW OF YOUR IT SECURITY
SIEM is essentially, nothing more than a management layer above your existing
systems and security controls.
It connects and unifies the information contained in your existing systems, allowing them
to be analyzed and cross-referenced from a single interface.
SIEM is a perfect example of the „Garbage In, Garbage Out‟ principle of computing :
SIEM is only as useful as the information you put into it.
The more valid information depicting your network, systems and behavior the SIEM
has, the more effective it will be in helping you make effective detections, analysis and
response in your security operations.

HALF A POUND OF LOGS, A CUP OF ASSET RECORDS….
Log Collection is the heart and soul of a SIEM – the more log sources that send logs to the
SIEM, the more that can be accomplished with the SIEM.
Logs on their own rarely contain the information needed to understand their contents within the
context of your business
Security Analysts have limited bandwidth to be familiar with every last system that your IT
operation depends on
With only the logs, all an analyst sees is “Connection from Host A to Host B”
Yet, to the administrator of that system, this becomes “Daily Activity Transfer from Point of
Sales to Accounts Receivable”.
The Analyst needs this information to make reasoned assessment of any security alert
involving this connection.
True value of logs is in correlation to get actionable information

SIEM RECIPES
A list of Ingredients to have a good SIEM Deployment
LOGS AND ALERTS:
Security Controls
Intrusion Detection
Endpoint Security (Antivirus, etc)
Data Loss Prevention
VPN Concentrators
Web Filters
Honeypots
Firewalls
Infrastructure
Routers
Switches
Domain Controllers
Wireless Access Points
Application Servers
Databases
Intranet Applications
KNOWLEDGE:
Infrastructure Information
Configuration
Locations
Owners
Network Maps
Vulnerability Reports
Software Inventory
Business Information
Business Process Mappings
Points of Contact
Partner Information

How a Log File is Generated in your Network

BEHOLD, THE POWER OF CORRELATION
Correlation is the process of matching events from systems (hosts, network
devices, security controls, anything that sends logs to the SIEM)
Events from different sources can be combined and compared against each other to
identify patterns of behavior invisible to individual devices…
They can also be matched against the information specific to *your* business.
Correlation allows you to automate detection for the things that should not occur on your
network.

THE BEAUTY OF LOG CORRELATION
Log Correlation is the difference between:
“14:10 7/4/20110 User BRoberts Successful Auth to 10.100.52.105 from
10.10.8.22”
and…
“An Account belonging to Marketing connected to an Engineering System from an
office desktop, on a day when nobody should be in the office”

SLOW COOK FOR 8 HOURS, SERVE TO HUNGRY ANALYSTS….
Your Network generates vast amounts of log data – a fortune 500 enterprise‟s
infrastructure can generate 10 Terabytes of plain-text log data per month, without
breaking a sweat.
You can‟t hire enough people to read every line of those logs looking for bad stuff. I‟m
serious, don‟t even try this. Even if you succeeded, they‟d be so bored they‟d never
actually spot anything even if it was right in front of their face.. Which it would be.
Log Correlation lets you locate the interesting places in your logs – that‟s where the
analysts start investigating from…
..And they‟re going to find pieces of information that lead to other pieces of information
as the trail of evidence warms up..
Being able to search through the rest of those logs for that one thing they suspect
resides there, is one of the other key functions of a SIEM….
It‟s a good thing that a SIEM is fundamentally a…..

…..GIANT DATABASE OF LOGS.
It would be amazingly useful if every operating system and every application in the
world, recorded their log events in the same format – they don‟t. Most logs are
written to be readable by humans, not computers.
That makes using regular search tools over logs from different sources… a little
difficult.
These two logs say the same thing to a human being, but are very different from
the machine‟s point of view.
“User Broberts Successfully Authenticated to 10.100.52.105 from client 10.10.8.22”
“100.100.52.105 New Client Connection 10.10.8.22 on account: Broberts: Success”
Long story short – we‟re going to need to break down every known log message out
there, into a normalized format.
“User [USERNAME] [STATUS] Authenticated to [DESTIP] from client [SOURCEIP]”
“100.100.52.105 New Client Connection 10.10.8.22 on account: Broberts: Success”
So when you see a SIEM Product that talks about “how many devices it supports” – it‟s talking about
how many devices it can parse the logs from.

SEARCHES, PIVOTING, AND CROSS-CORRELATION
Breaking those log entries down into their components – normalizing them, is what
allows us to search across logs from multiple devices, and correlate events between
them.
Once we‟ve normalized logs into a database table, we can do database style
searches, such as :
“Show [All Logs] From [All Devices] from the [last two weeks], where the [username]
is [Broberts]”
This is what allows us to do automated correlation as well, matching fields between log
events, across time periods, across device types.
“If A single Host fails to log in to three separate servers using the same credentials,
within a 6-second time window, raise an alert”
Just as with any database, event normalization allows the creation of report
summarizations of our log information
“What User Accounts have accessed the highest number of distinct hosts in the last month?”
“What Subnet generate the highest number of failed login attempts per day, averaged out
over 6 months?”

BUT WAIT, THERE’S MORE!
So you‟ve now seen that SIEM is a recording device for the systems that form your information
infrastructure.
SIEM allows you to give analysts access to information from these systems, without giving them
access to the systems themselves.
Event Correlation allows you to encode security knowledge into automated searches across
events and asset information to alert on things happening within your infrastructure, and create
a starting point for human analysis into a sea of log data.
But, to keep up with today‟s threat landscape you need more that just SIEM – you need relevant
data, a unified approach and integrated threat intelligence to truly get a holistic view of your
security posture.
OBLIGATORY PRODUCT PITCH TIME: AlienVault USM and OSSIM (Open-source
version), are designed to include many data sources as part of core product and provides the
threat intelligence to stay ahead.

MANY POINT SOLUTIONS…INTEGRATION ANYONE?
OR
AlienVault USM

powered by
AV Labs Threat
Intelligence
USM ASSET DISCOVERY
• Active Network Scanning
• Passive Network Scanning
• Asset Inventory
• Host-based Software
Inventory
VULNERABILITY ASSESSMENT
• Continuous Vulnerability
Monitoring
• Authenticated / Unauthenticated
Active Scanning
BEHAVIORAL MONITORING
• Log Collection
• Netflow Analysis
• Service Availability Monitoring
SECURITY INTELLIGENCE
• SIEM Event Correlation
• Incident Response
THREAT DETECTION
• Network IDS
• Host IDS
• Wireless IDS
• File Integrity Monitoring
ALIENVAULT USM BRINGS IT ALL TOGETHER
AlienVault USM starts at $3600

Features: AlienVault USM Traditional SIEM
Log Management ✔ ✔
Event Management ✔ ✔
Event Correlation ✔ ✔
Reporting ✔ ✔
Asset Discovery ✔ $$
3rd-party product that requires integration
Network IDS ✔ $$
Host IDS ✔ $$
Wireless IDS ✔ $$
NetFlow ✔ $$
Full Packet Capture ✔ $$
Vulnerability Assessment ✔ $$
Continuous Threat Intelligence ✔ Not Available
Unified Console for Security
monitoring technologies
✔ Not Available

Play, share, enjoy!
RECOMMENDED NEXT STEPS:
Learn more about our commercial offering
• Try AlienVault USM, free for 30 days
• Join us for a LIVE Demo (hosted every
Thursday)
Or try our Open Source version
• Download OSSIM
Join the Open Threat Exchange (OTX)
, the world‟s largest crowd-sourced threat
sharing repository.

Beginner's Guide to SIEM

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