INTRUSION DETECTION SYSTEMS (IDS) INTRODUCTION AND OVERVIEW (What vendors will not tell you) - PowerPoint PPT Presentation

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INTRUSION DETECTION SYSTEMS (IDS) INTRODUCTION AND OVERVIEW (What vendors will not tell you)

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  1. INTRUSION DETECTION SYSTEMS (IDS)INTRODUCTION AND OVERVIEW(What vendors will not tell you) Clément Dupuis,CDCISSP, GCFW, GCIACCSA, CCSE, ACECGI Group / CCCure.Org

  2. OVERVIEW Network versus host based IDS C-I-A Challenges Choosing an IDS (Criteria & Features) Products available on market Ongoing Effort Conclusion More Info • INTRODUCTION • Overview • Definitions & Jargon • The Puzzle • Current State of IDS • Threats (Fact or fiction) • I have a good firewall, why do I need an IDS? • Realistic expectations • ID Landscape • Type of IDS

  3. Intrusion Detection Definition: • Defined by ICSA as: • The detection of intrusions or intrusions attempts either manually or via software expert systems that operate on logs or other information available from the system or the network. • An intrusion is a deliberate, unauthorized attempt to access or manipulate information or system and to render them unreliable or unusable. • When suspicious activity is from your internal network it can also be classified as misuse

  4. Jargon related to IDS • False Negative • False Positive • Beware, companies uses different names for exactly the same type of detect. • What is a DMZ ? • How to count- what is byte 9 ? Is it the tenth byte or really the ninth

  5. The Puzzle • Intrusion Detection Systems are only one piece of the whole security puzzle • IDS must be supplemented by other security and protection mechanisms • They are a very important part of your security architecture but doesnot solve all your problems • Part of “Defense in depth”

  6. Current State of IDS • Lots of people are still using Firewall and Router logs for Intrusion Detection (Home Brew) • IDS are not very mature • Mostly signature based • It is a quickly evolving domain • Giant leap and progress every quarter • As stated by Bruce Schneier in his book ‘Secret and Lies in a digital world’: PreventionDetection  Getting to this point todayReponse

  7. OVERVIEW Network versus host based IDS C-I-A Challenges Choosing an IDS (Criteria & Features) Products available on market Ongoing Effort Conclusion More Info • INTRODUCTION • Overview • Definitions & Jargon • The Puzzle • Current State of IDS • THREATS • I have a good firewall, why do I need an IDS? • Realistic expectations • ID Landscape • Type of IDS

  8. THREATS – FACT OR FICTION ?? • Frequency vs Difficulty level • I am not a target (Yeah, right!) • Examples of TOOLS • Recent vulnerabilities • A classic example: CODERED • Hacktivists or cyber terrorists • The BIGGEST threat

  9. Frequency vs Difficulty level • The frequency of probes, attacks, or intrusions attempts is inversely proportional to the difficulty level required to perform such attacks. • A clear trend has been identified over the past 3 years. Graphical tools that are getting very sophisticated have replaced the combersome command line utilities. • They are now available for Windows as well as other platforms. • It is no longer necessary to have any computer knowledge to break through defense mechanisms that are not properly maintained.

  10. Who are the targets ?? • Simply being connected is a good enough reason to be a target. Search is ongoing for easy to compromise hosts. • Fast bandwidth is now a cheap commodity. • Cable modem and ADSL access is the equivalent of having a T1 link in your home. • Kids of all ages can scan a whole country in a very short time frame. • No specific motive: They do it for fame, fun, to show off, or just because they have nothing else to do. No technical knowledge is required to be a ‘’Script Kiddie’’

  11. E-COMMERCE + WELL KNOWN NAME = HACKER TARGET • A clear example is the Denial of service attacks against Yahoo, Ebay, and other popular sites. • ISCA Info Security Magazine Sept 2000 • Comparison E-Comm site (left column) vs Non E-Comm site (right column) Viruses/Trojan/worm 82% 76% Denial of service 42% 31% Active Scripting exploit 40% 34% Protocol Weaknesses 29% 23% Insecure Passwords 30% 20% Buffer Overflow 29% 20% Bugs in web server 33% 16%

  12. HACKING TOOLS (EASY TO GET, EASY TO USE, VERY POWERFULL)

  13. My friend SAM SPADE

  14. Execution of arbitrary command through HTTP(10/10/2000) http://address.of.iis5.system/scripts/..%c1%1c../winnt/system32/cmd.exe?/c+dir+c:\ • OUTPUT:Directory of c:\ 2000-08-08 18:28 Inetpub 2000-08-09 09:58 Install 2000-08-09 11:17 MDaemon 2000-09-01 09:01 MSSQL7 2000-08-29 13:03 news 2000-10-18 02:53 ooo 2000-10-18 01:37 Program Files 2000-08-09 17:54 sttco 2000-10-17 11:48 WINNT 2000-10-18 02:02 wwww 2000-09-26 12:03 1 File(s) 28,160 bytes 14 Dir(s) 6,377,992,192 bytes free • NOTE:%c0%af and %c1%9c are UNICODE representation for the / and \ characters

  15. Plain text password after Directory Server Install (10/04/2000) • After installing Netscape's Directory Server 4 for Solaris, one of the final options is to remove a file called 'install.inf' which the install process claims could contain sensitive information. Answering yes to this question will delete the file. • However there is another file left behind after installation which contains the un-encrypted 'admin' password. This file has world read permissions and is located in /usr/netscape/server4/admin-serv/config/adm.conf

  16. CODERED • Yet, another buffer overflow • Disguise as HTTP request • Goes on to infect other systems • Could have been stopped by granular access control, proper FW configuration • It is not normal traffic when your web server is surfing the internet and making outbound requests on port 80

  17. THE TOP 10 INTERNET THREATS(Top 10 from SANS Institute) • Bind weakenesses • Vulnerable CGI and extension on web server • Remote Procedure (NFS and Remote execution) • IIS Remote Data Services (for example .htr files) • Sendmail Buffer Overflow • Solaris sadmind and mountd • IMAP/POP buffer overflow or incorrect configuration • Default SNMP community strings set to ‘public’ and ‘private.’ • Global file sharing (netbios, Macintosh web sharing, UNIX NFS) • Use of weak password or no password on user id

  18. Hacktivists or Cyber terrorists • USA TODAY October 9th 2001 • Very Likely • Denial of services attack • Computer worms and viruses • Likely • Breaking into government computer and stealing military secrets or encryption technology • Power grid disruption • Emergency system being compromised • Other internet connected services disruption

  19. Hacktivist or Cyber terrorists • Unlikely • Cutting off fiber-optic cables between major hubs • Bombing or physically attacking domain name servers or switching centrals. • Bombing of internet facilities to take down the Internet

  20. Digging a Tunnel • You spend great money on concrete walls (firewalls) but they are of no use of someone can dig through them. RelTunnel – ICMP Tunnel

  21. The biggest threat: EXPOSURE • The biggest threat of all is bad publicity and having your company reputation and name associated with an intrusion, site modification and defacement, or even attack to other sites using your ressources as a launch platform. • It could kill all faith in the belief that you can offer a secure environment to conduct E-Commerce or other online activities. • Even thou perception is often not the reality. Outsider and customers does not care that the specific site was on a bronze plan or that it was not hosted in house. • PEOPLE ONLY READ LARGE TITLES such as: ‘’XYZ GOT HACKED!!!’’

  22. OVERVIEW Network versus host based IDS C-I-A Challenges Choosing an IDS (Criteria & Features) Products available on market Ongoing Effort Conclusion More Info • INTRODUCTION • Overview • Definitions & Jargon • The Puzzle • Current State of IDS • Threats (Fact or fiction) • WHY AN IDS? • Realistic expectations • ID Landscape • Type of IDS

  23. WHY DO I NEED AN IDS, I HAVE A FIREWALL? • IDS are a dedicated assistant used to monitor the rest of the security infrastructure • Today’s security infrastructure are becoming extremely complex, it includes firewalls, identification and authentication systems, access control product, virtual private networks, encryption products, virus scanners, and more. All of these tools performs functions essential to system security. Given their role they are also prime target and being managed by humans, as such they are prone to errors. • Failure of one of the above component of your security infrastructure jeopardized the system they are supposed to protect

  24. WHY DO I NEED AN IDS, I HAVE A FIREWALL? • Not all traffic may go through a firewall i:e modem on a user computer • Not all threats originates from outside. As networks uses more and more encryption, attackers will aim at the location where it is often stored unencrypted (Internal network) • Firewall does not protect appropriately against application level weakenesses and attacks • Firewalls are subject to attacks themselves • Protect against misconfiguration or fault in other security mechanisms

  25. REAL LIFE ANALOGY • It's like security at the airport... You can put up all the fences in the world and have strict access control, but the biggest threat are all the PASSENGERS (packet) that you MUST let through! That's why there are metal detectors to detect what they may be hiding (packet content). • You have to let them get to the planes (your application) via the gate ( port 80) but without X-rays and metal detectors, you can't be sure what they have under their coats. • Firewalls are really good access control points, but they aren't really good for or designed to prevent intrusions. • That's why most security professionals back their firewalls up with IDS, either behind the firewall or at the host.

  26. OVERVIEW Network versus host based IDS C-I-A Challenges Choosing an IDS (Criteria & Features) Products available on market Ongoing Effort Conclusion More Info • INTRODUCTION • Overview • Definitions & Jargon • The Puzzle • Current State of IDS • Threats (Fact or fiction) • I have a good firewall, why do I need an IDS? • EXPECTATIONS • ID Landscape • Type of IDS

  27. WHAT CAN IDS REALISTICLY DO • Monitor and analyse user and system activities • Auditing of system and configuration vulnerabilities • Asses integrity of critical system and data files • Recognition of pattern reflecting known attacks • Statistical analysis for abnormal activities • Data trail, tracing activities from point of entry up to the point of exit • Installation of decoy servers (honey pots) • Installation of vendor patches (some IDS)

  28. WHAT IDS CANNOT DO • Compensate for weak authentication and identification mechanisms • Investigate attacks without human intervention • Guess the content of your organization security policy • Compensate for weakeness in networking protocols, for example: IP Spoofing • Compensate for integrity or confidentiality of information • Analyze all traffic on a very high speed network • Deal adequately with attack at the packet level • Deal adequately with modern network hardware

  29. OVERVIEW Network versus host based IDS C-I-A Challenges Choosing an IDS (Criteria & Features) Products available on market Ongoing Effort Conclusion More Info • INTRODUCTION • Overview • Definitions & Jargon • The Puzzle • Current State of IDS • Threats (Fact or fiction) • I have a good firewall, why do I need an IDS? • Realistic expectations • LANDSCAPE • Type of IDS

  30. ID TECHNOLOGY LANDSCAPE PREVENTIVE REAL TIME

  31. TYPE OF IDS MONITORING • Home Brew (Script, Big Brother, Logwatch, swatch) • Application Based • Host Based (also called Agent) • Target Based approach • Integrity checker such as the tripwire tool. • Network Based (also called Sensor) • Hybrid or Integrated approach (Use all or a combination of two or more of the above) • Honeypot, Honeynet, and the Sticky Honeypot • Gateway IDS (IDS/FW Combined)

  32. TYPE OF ANALYSIS • Signature based (Pattern matching) • Similar to a virus scanner, look for a specific string in the network data being presented to the IDS • Statistical • Based on time, frequency, lenght of session • For example: cdupuis logs on at 0300 AM and has never done so in the past, it will raise a flag • Integrity Checker • Based on hashing mechanism. Detects authorized and unauthorized changes to files within your systems. • Anomaly Detection/Behavior Based • Flow Based

  33. TYPE OF RESPONSE • Alteration to the environment • Changes a rule on router • Changes a rule on Firewall • Striking back (not recommended) • Execute a script to collect information about attacker • Send a 20 megs file back to anyone fingering • Down side: Acknowledgement sent to the attacker • Real time notification • Send a pager alert • SNMP Alarms • Sends email to one or more recipients • Visual on screen or audible alarms

  34. TYPE OF RESPONSE • Throttling • Limiting rate • Slowing down attacks • Session Sniping • Will hijack a session • Sends a reset to both side of session

  35. OVERVIEW NETWORK vs HOST C-I-A Challenges Choosing an IDS (Criteria & Features) Products available on market Ongoing Effort Conclusion More Info • INTRODUCTION • Overview • Definitions & Jargon • The Puzzle • Current State of IDS • Threats (Fact or fiction) • I have a good firewall, why do I need an IDS? • Realistic expectations • ID Landscape • Type of IDS

  36. HOST BASED (Advantages) • Monitor in term of who accessed what • Can map problem activities to a specific user id • System can track behavior changes associated with misused • Can operate in encrypted environment • Operates in switched networks • Monitoring load distributed against multiple hosts and not on a single host, reporting only relevant data to central console

  37. HOST BASED (Disavantages) • Cannot see all network activities • Running audit mechanisms adds overload to system, performance may be an issue • Audit trails can take lots of storage • OS vulnerabilities can undermine the effectiveness of agents • Agents are OS specific • Escalation of false positive • Greater deployment and maintenance cost

  38. NETWORK BASED (Advantages) • Can get information quickly without any reconfiguration of computers or need to redirect logging mechanisms • Does not affect network or data sources • Monitor and detects in real time networks attacks or misuses • Does not create system overhead

  39. NETWORK BASED (Disavantages) • Cannot scan protocols if the data is encrypted • Can infer from network traffic what is happening on host but cannot tell the outcome • Hard to implement on fully switched networks • Has difficulties sustaining network with a very large bandwidth

  40. OVERVIEW Network versus host based IDS C-I-A Challenges Choosing an IDS (Criteria & Features) Products available on market Ongoing Effort Conclusion More Info • INTRODUCTION • Overview • Definitions & Jargon • The Puzzle • Current State of IDS • Threats (Fact or fiction) • I have a good firewall, why do I need an IDS? • Realistic expectations • ID Landscape • Type of IDS

  41. WHAT DOES IT PROTECT ME AGAINST

  42. WHAT DOES IT PROTECT ME AGAINST

  43. OVERVIEW Network versus host based IDS C-I-A CHALLENGES Choosing an IDS (Criteria & Features) Products available on market Ongoing Effort Conclusion More Info • INTRODUCTION • Overview • Definitions & Jargon • The Puzzle • Current State of IDS • Threats (Fact or fiction) • I have a good firewall, why do I need an IDS? • Realistic expectations • ID Landscape • Type of IDS

  44. CHALLENGES • Deployment & Myths • Using IDS in fully switched networks • Substaining OC3 speed or higher • Interpreting all the data being presented • Encryption, VPN, Tunnels • Ongoing Support • Performance • Response team

  45. Deployment & Myths • Deployed before or after the firewall • One IDS per segment • The more rule in the product the better the product. • Real Time • 100% Security

  46. Fully Switched & Redundant

  47. CAN’T SEE, CAN’T TELL

  48. RESPONSE TEAM • An IDS deployment will be only as successful as the Incident Handling procedures that are in place to support it. • It shoud include: • Statement of scope • Acceptable computer and network use • Detection and reporting requirements • Responsabilities for responding to incidents • Responsabilities for managing incident response

  49. Evasion Techniques • Evasion techniques are used in order to navigate below the radar of your IDS • Fragmentation • Slow scan • Stealth scan • Out of order packets • Ambiguous packet (crafting) • Encoding such as %u, UTF (%xx%xx), HEX (%xx) • Use of well known port (Codered) Extra reading: http://secinf.net/info/ids/idspaper/idspaper.html

  50. Evasion Techniques - %u encoding • Announced 5 Sept 2001 by eEye Digital Security • Almost all IDS are vulnerable except SNORT, Symantec, and NAI • Not a standard and only MS specific, unknown to other vendors. • So if an attacker sent a %u encoded request then they could bypass IDS checking for ".ida". • An example stealth codered request would look like: GET /himom.id%u0061 HTTP/1.0