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Conducting Defensive Information Warfareon
Open Platforms
Ben Tullis – (formerly of) LinuxIT (Europe) Ltd.
23rd October 2013 – LinuxCon Europe
Ben Tullis - Background
● Professional Linux sysadmin (etc.) for 12+ years● Worked in several markets:
– Independent Software Vendor
– UK Government Research: (British Antarctic Survey)
– Managed Services Providers
– Specialist Linux Consultancy
● Broad experience of Linux and IT security:– ...in the SME Sector
– ...in the Outsourced Enterprise Sector
Presentation Topics
Defensive Information Warfare on Open Platforms
● Definitions, Threats, Targets, The Basics
● Increasing Network Visibility
● Increasing Host Visibility
● Log Management Tools & Techniques
● Collating and Presenting Security Information
● Focused Distributions
What is Information Warfare?
It's a model that helps to achieve good security practice.
Comprised of four key elements:
1: Information Resources
These resource have intrinsic value to someone:
● Exchange value – how much is it worth?
● Operational value – how useful/important is it?
What is Information Warfare?
2: Players of The Game
Offence– In this context, the enemy.
– Could be anyone with Motive, Means & Opportunity to launch an attack on an Information Resource
– One or more of: insiders, hackers, criminals, corporations, governments, and terrorists
– Those ever-present “unknown unknowns”
Defence– Everyone else, from individuals to governments
– Anyone with Information Resources to protect
– In this context, us
What is Information Warfare?
3: Offensive OperationsTheir aim is to:
● Increase the value of an Information Resource to an Offensive player.
● Decrease the value of an Information Resource to a Defensive player.
Three classes of attack
Increased availability of information for the offence e.g. espionage, identity theft, physical theft
Decreased integrity of information e.g. tampering, fabrication, perception management
Decreased availability of information for the defence e.g. sabotage, denial of service, physical theft
What is Information Warfare?
4: Defensive OperationsTheir aim is to:
● Protect Information Resources from these three forms of attack.
They must:
● Cost less than the losses that would occur in their absence.
Six classes of defensive operation● Prevention
● Deterrence
● Indications and Warnings
● Detection
● Emergency Preparedness
● Response
Random Threats - Can affect anyone equally
Examples:● Malware distribution:
– Removable Media
– Infected Downloads
● IP Address scanning:– Brute-force attacks
– Zero-day attacks
– e.g. Carna Botnet (420k node bot-net created by using default passwords)
● Wardriving● Session Hijacking
Focused Threats - We are the target
● Traditional Network Penetration:– Dictionary Attacks
– Off-line Attacks (e.g. Cloudcracker)
● Known Exploits:– Vulnerable Network Services
– Privilege Escalation
● Social Engineering
Focused Threats - We are the target
Stealthy Devices: Requiring physical access
– Dropboxes e.g.● Pwnie Express● MiniPwner● Pwn Pi
– Rogue Access Point e.g.● WiFi Pineapple
– Key Stroke Loggers
– Miniature Cameras etc.
Defining the Targets
They are/will beeverywhere.
Defending Information – The Basics
● Good documentation & communication
● Good passwords & security policies
● Appropriate physical security measures
● Well defined change-management procedures
● Apply security patches promptly
● Standardize where possible/appropriate
● Back it all up
Defending Information – The Basics
● Your Monitoring Solution TM – Monitor everything you can think of
– Record as many metrics as possible
– Review its configuration periodically and...● ...in response to change● ...in response to significant incidents
– If appropriate, use multiple/parallel systems.● Availability Monitoring● Performance Monitoring● Network Security Monitoring
Increasing Network Visibility - Overview
Making the best possible haystack/needle finding machine:– Capture as much network traffic as possible
– Scan captured traffic: NIDS
– Consider wireless protocols: WIDS
– Profile network traffic:● Record detailed statistical information● Visualise normal network behaviour● Facilitates filtering-out of legitimate traffic
– Implement anomaly detection
Capturing Ethernet Traffic
Often use Switch Mirror Ports (aka. SPAN or Monitor Port)
One port receives all traffic sent to/from the other ports.
Most smart/managed switches support this feature.
Another technique is to use a Network Tap
# ifconfig eth1 up promisc# ifconfig eth1 up promisc
Capturing Ethernet Traffic
Simplest case:
● All traffic passing through the switch is visible at the protective Monitoring Server
● Do not assign an IP address to the capture interface:
Capturing Ethernet Traffic
Redundant System:
● Dual interfaces on all servers: active/active or active/passive
● One capture interface per switch
Capturing Ethernet Traffic
Tree Topology - Option 1 – Remote Port Mirroring
● Requires high-end switches. e.g. Cisco, HP, H3C, Alcatel● Send all captured traffic to a central location for analysis/profiling.● Upgrade interface links as necessary.● Uses VLANs to isolate the mirrored traffic.● Fairly complex to configure.
Capturing Ethernet Traffic
Tree Topology - Option 2 – Distributed MonitoringRequires several capture servers
Remote servers send back:● Events & Alerts● Statistical traffic information● System log files
Network Intrusion Detection Systems
Snort– Passive mode – Intrusion Detection
– Inline mode – Intrusion Prevention
– Searches network traffic for pattern matches
– Rules files updated daily● Up-to-date VRT rules available immediately to subscribers● VRT rules freely available to registered users after 30 days● Community rules under GPL. A subset of the VRT rules● Third-party rule sets available. e.g.
http://www.emergingthreats.net
Network Intrusion Detection Systems
Snort– Update rules daily with one of:
● Oinkmaster● Pulled Pork
– Expect to spend some time tuning:● Main config file: snort.conf● Rules files● Ethernet interface configuration
e.g. Disable ”Large Receive Offload” and ”Generic Receive Offload” on the collector:
ethtool -K eth1 gro offethtool -K eth1 lro off
ethtool -K eth1 gro offethtool -K eth1 lro off
Network Intrusion Detection Systems
Snort– Each rule has an Action associated, e.g.
● Send an alert and log traffic.● Simply drop the offending packets. (Inline mode)● Reject the traffic: TCP reset. UDP unreachable. (Inline mode)● Custom actions & custom log types
– Very flexible alerting and logging methods, e.g.● Text → email alert & Pcap log file● Syslog alert & logging to database● Unified2 (recommended, high-performance format)
Network Intrusion Detection Systems
Suricata
● IDS/IPS project started in 2009– Multi-threaded for greater native performance
– Unified2 output by default
– Protocol detection. Not based on port number
– File identification by md5. Extract and save files from traffic
– Can use Snort rules and can co-exist
– http://suricata-ids.org/
Network Intrusion Detection Systems
Bro
● Passive Network Analysis Platform:– IDS features available – require custom scripting.
– Detailed statistical log files created
– Application-layer transcripts, e.g. HTTP, SSL etc.
– Cluster-aware for high-capacity analysis
– Scripting engine : Highly extensible
– Match MD5 against Team Cymru malware database
Wireless Intrusion Detection Systems
● Current best practice in IEEE 802.11:– Implement WPA2-Enterprise
● RADIUS – e.g. FreeRADIUS● EAP – Strong Authentication● hostapd + wpa_supplicant [+ OpenSSL]
– Implement IEEE 802.11w
● Management Frames Protected
● We consider two types of attack:– A Rogue Access Point
– A De-Authentication Attack
Wireless Intrusion Detection Systems
Kismet● Monitor 802.11 traffic for known attack patterns:
– Use additional wireless radios in monitor mode
– (optionally) Channel-hop on the channels that you use
– Drones can be distributed network-wide
– Suitable for embedded use i.e. OpenWRT, DD-WRT etc.
– Client can view real-time client list and traffic
– Alerts can be sent via syslog
– Tap interface permits full 802.11 capture
Wireless Intrusion Detection Systems
Kismet1: Detecting rogue access points
Legitimate Clients
Wireless Intrusion Detection Systems
Kismet1: Detecting rogue access points
ncsource=drone1:host=10.10.100.1,port=2502ncsource=drone2:host=10.10.100.2,port=2502
alert=APSPOOF,10/min,1/secapspoof=Tullix:ssid="Tullix",validmacs="00:11:22:33:44:55,AA:BB:CC:DD:EE:FF"
allowplugins=true
ncsource=drone1:host=10.10.100.1,port=2502ncsource=drone2:host=10.10.100.2,port=2502
alert=APSPOOF,10/min,1/secapspoof=Tullix:ssid="Tullix",validmacs="00:11:22:33:44:55,AA:BB:CC:DD:EE:FF"
allowplugins=true
Kismet
● On the server: kismet.conf
● On the drones: kismet_drone.conf
ncsource=wlan0:drone1:channellist=Tullix
dronelisten=tcp://10.10.100.1:2502droneallowedhosts=10.10.0.1
ncsource=wlan0:drone1:channellist=Tullix
dronelisten=tcp://10.10.100.1:2502droneallowedhosts=10.10.0.1
Wireless Intrusion Detection Systems
Kismet2: Detecting a de-authentication attack
Wireless Intrusion Detection Systems
Kismet2: Detecting a de-authentication attack
ncsource=drone1:host=10.10.100.1,port=2502ncsource=drone2:host=10.10.100.2,port=2502
alert=DEAUTHFLOOD,5/min,2/secalert=BCASTDISCON,5/min,2/sec
allowplugins=true
ncsource=drone1:host=10.10.100.1,port=2502ncsource=drone2:host=10.10.100.2,port=2502
alert=DEAUTHFLOOD,5/min,2/secalert=BCASTDISCON,5/min,2/sec
allowplugins=true
● On the server: kismet.conf
Network Traffic Profiling
Ntop and NtopNG● Near real-time and historical information about:
– Hosts observed
– Protocol distribution
– Multicast/Broadcast frequency
– Who's talking to whom?
● Rich graphical interface● Can also be used as a NetFlow Collector● PF_RING allows multi-threaded libpcap analysis
Network Traffic Profiling - NtopNG
Network Traffic Profiling - Ntop
NetFlow and friends
● A UDP protocol describing network traffic● Many proprietary formats: NetFlow, sFlow, jflow, Rflow● IETF proposed standard: IPFIX (== NetFlow v10)
NetFlow Exporters
● Native support in high-end switches routers● Open Source exporters based on Libpcap (& PF_RING)
– Nprobe - http://www.ntop.org/products/nprobe/
– Fprobe - http://fprobe.sourceforge.net/
– Softflowd - http://code.google.com/p/softflowd/
– Rflow - https://en.wikipedia.org/wiki/DD-WRT#Features
● Also a feature of Open vSwitch - http://openvswitch.org/● Netflow v5 and v9 are the most common formats
● Exporters send UDP packets to one or more collectors
NetFlow Collectors
Ntop – Historical and statistical analysis
Nfdump / NfSen – Long-term NetFlow storage and detailed query– Nfdump tool-set
● nfcapd – Collect netflow streams and save the information● nfdump – Extract and report information from the stored files● nfprofile – Report on a subset of traffic from the stored files
– NfSen web-interface● Web front-end to analyse and query Nfdump files● Dynamic graph generation, based on filters and time periods
NfSen – NetFlow Sensor
Anomaly Detection Tools
● Arpwatch / Arpalert– Maintain a database of authorized MAC addresses
– Alert on any deviation – syslog or email
● PRADS - Passive Real-Time Asset Detection System– Builds a list of hosts/service on the network
– Can be used to inform snort configuration
– pradsassetreport - what's been seen on the network?
● PBNJ – Active Network Asset Detection System– Database of discovered hosts/services (nmap)
– Re-scan & diff
Increasing Host Visibility - Overview
● Useful host-based tools
● Host-based Intrusion Detection Systems (HIDS)
Host Visibility Tools
● etckeeper – Keep /etc under version control
Host Visibility Tools
● atop – Retain Historical Process Information
Host Visibility Tools
● auditd – The Linux Audit Daemon
– and audispd – The Linux Audit Dispatcher
Host Visibility Tools
● lynis – Security audit script, with hardening suggestions
Host-based Intrusion Detection Systems
● OSSEC– Multi-platform – facilitates distributed security monitoring
– File integrity monitoring
– Log file monitoring
– Rootkit search
– Policy audit
– Email/syslog alerts
– SQL output
Host-based Intrusion Detection Systems
● Samhain - File Integrity Monitor– Client/Server mode
– Stand-alone mode
– Log file monitoring
– Hidden processes
– Stealth mode
– auditd integration
– SQL output
– Syslog output
● Beltane - web front-end
Host-based Intrusion Detection Systems
● Tripwire – Lightweight file integrity monitor– Define policy for file monitoring
– Create checksum databases of a clean system
– Mount /var/lib/tripwire on R/O media or R/O network share
– Checked by cron daily – email/syslog alert on change
– Update databases and policies as required
– Configuration, Policies and Databases digitally signed, requiring pass-phrase to update
Host-based Intrusion Detection Systems
● AIDE – Advanced Intrusion Detection System– Similar in scope and operation to Tripwire
– Simpler configuration including conf.d snippets
● Fcheck – Perl based file integrity monitor– Older but dependable and useful in certain environments
● Stealth – Remote file integrity monitor over SSH– http://stealth.sourceforge.net
Log File Management
● syslog – Generally using rsyslog or syslog-ng now– Centralize logs – including switches, routers, etc.
– e.g. Snare or eventlog-to-syslog for Windows
– TCP or RELP (rsyslog) can aid reliable network transfer
● Cryptographic Log Signing (GPG-13 requirement)– Feature of rsyslog version 7.4+
– rsgutil utility verifies signaturesaction(type="omfile" file="/var/log/syslog" sig.provider="gt" sig.keepTreeHashes="on" sig.keepRecordHashes="on")
action(type="omfile" file="/var/log/syslog" sig.provider="gt" sig.keepTreeHashes="on" sig.keepRecordHashes="on")
Log File Management
● Visualize/Analyse syslog data– e.g. Addiscon Loganalyzer [sic]
Log File Management
● Visualize/search syslog data – alternatives
– ElasticSearch
– Graylog2
– Logstash
– Kibana
– ELSA
Log File Management
● Application Logs – e.g. Web server– Google Analytics != Web Log Analysis
– Piwik Log Analytics Mode - http://piwik.org/log-analytics/
Active Response – Intrusion Prevention
● Snortsam – Firewall hosts using a Snort plugin– Agent runs on/near firewall
● fail2ban - Firewall hosts from log file matches– Authentication
Failures
– Repeat Offender Handling
Collating and Presenting Security Information
● Sagan – Scan log files for security related information– Snort-like rules for pattern matching
– e.g. Handling our previous WIDS alert
alert syslog $EXTERNAL_NET any -> $HOME_NET any (msg: "[KISMET] Spoofed disassociated/deauthenticate packets"; program: kismet_server; pcre: "/DEAUTHFLOOD|BCASTDISCON/"; classtype: suspicious-traffic;)
alert syslog $EXTERNAL_NET any -> $HOME_NET any (msg: "[KISMET] Spoofed disassociated/deauthenticate packets"; program: kismet_server; pcre: "/DEAUTHFLOOD|BCASTDISCON/"; classtype: suspicious-traffic;)
– Incorporate results into an IDS database
– Integrates with Snortsam Agent for active firewall response
Collating and Presenting Security Information
● Snorby – Web console collating IDS/IPS and Sagan alerts
– Integrates with OpenFPC for full packet capture
● Other consoles available – e.g. Sguil & Squert, BASE
Focused Distributions
● AlienVault OSSIM : (Debian based)
– Open Core version of their full-featured USM product● Nagios● NfSen● OSSEC● Kismet● Snort● Suricata● Ntop● Arpwatch● PADS● OpenVAS
– Custom Correlation Engine
– Custom web framework
Focused Distributions
● The Security Onion : (Ubuntu based)
● Snort● Suricata● Bro● Sguil● Squert● Snorby● ELSA● Netsniff-NG● OSSEC● PRADS● Xplico● NetworkMiner● CapME● Argus
Summary
Conducting Defensive Information Warfare
● Maximum network visibility
● Maximum host visibility
● Rigorous log file management
● Rapid analysis and response
Image attributions
Thanks to Creative Commons:
● http://www.flickr.com/photos/pasukaru76/5108255589/
● http://idle.slashdot.org/story/08/10/01/231247/man-uses-remote-logon-to-help-find-laptop-thief
● http://www.article-3.com/criminal-law-laptop-theft-protection-92052
● http://www.flickr.com/photos/pingdom/5370307776/
● http://www.geograph.org.uk/photo/2472373
● http://hakshop.myshopify.com/products/wifi-pineapple-holiday-bundle
● http://www.cctvcameradvrs.com/4gb-mini-spy-camera-with-voice-control
● http://www.flickr.com/photos/fastjack/282707058/
● http://www.insuretrust.com/study-finds-cyber-crime-costly-ever
● http://www.telegraph.co.uk/technology/news/8262628/Cyber-attacks-could-cause-global-catastrophe.html
● http://mtitechsolutions.com/blog/types-of-attacks.html
● http://en.wikipedia.org/wiki/File:Snort_ids_logo.png
● http://www.bro.org
● http://commons.wikimedia.org
● https://en.wikipedia.org/wiki/File:NetFlow_Architecture_2012.png
● http://nfsen.sourceforge.net/
● http://www.ossec.net/doc/manual/ossec-architecture.html
● http://logstash.net/images/logstash.png
● http://deinoscloud.wordpress.com/2012/11/01/esxigraylog2-quickstart/
● http://www.elasticsearch.org/
● http://www.jesuisungeek.net/index.php?post/2013/01/31/Installer-Kibana-par-Puppet-partie-1
● http://munin.alexdpsg.net/alexdpsg.net/munin.alexdpsg.net/fail2ban-month.png
● http://en.wikipedia.org/wiki/File:Alienvault_capture.png
● http://openclipart.org
Explicit Permission Granted:
● Pwnie Express - http://pwnieexpress.com/
● MiniPwner - http://www.minipwner.com/
