4.8 Incident Response Flashcards
Security incidents
User clicks an email attachment and executes malware
– Malware then communicates with external servers
* DDoS
– Botnet attack
* Confidential information is stolen
– Thief wants money or it goes public
* User installs peer-to-peer software and allows
external access to internal servers
NIST SP800-61
National Institute of Standards and Technology
– NIST Special Publication 800-61 Revision 2
– Computer Security Incident
– Handling Guide
* The incident response lifecycle:
– Preparation
– Detection and Analysis
– Containment, Eradication, and Recovery
– Post-incident Activity
Preparing for an incident
Communication methods
– Phones and contact information
* Incident handling hardware and software
– Laptops, removable media, forensic software,
digital cameras, etc.
* Incident analysis resources
– Documentation, network diagrams, baselines,
critical file hash values
* Incident mitigation software
– Clean OS and application images
* Policies needed for incident handling
– Everyone knows what to do
The challenge of detection
Many different detection sources
– Different levels of detail, different levels of perception
* A large amount of “volume”
– Attacks are incoming all the time
– How do you identify the legitimate threats?
* Incidents are almost always complex
– Extensive knowledge needed
– Analysis
* An incident might occur in the future
– This is your heads-up
* Web server log
– Vulnerability scanner in use
* Exploit announcement
– Monthly Microsoft patch release,
– Adobe Flash update
* Direct threats - A hacking group doesn’t like you
Analysis
An attack is underway - Or an exploit is successful
* Buffer overflow attempt
– Identified by an intrusion detection/prevention system
* Anti-virus software identifies malware
– Deletes from OS and notifies administrator
* Host-based monitor detects a configuration change
– Constantly monitors system files
* Network traffic flows deviate from the norm
– Requires constant monitoring
Isolation and containment
Generally a bad idea to let things run their course
– An incident can spread quickly
– It’s your fault at that point
* Sandboxes
– An isolated operating system
– Run malware and analyze the results
– Clean out the sandbox when done
* Isolation can be sometimes be problematic
– Malware or infections can monitor connectivity
– When connectivity is lost, everything could be
deleted/encrypted/damaged
Recovery after an incident
Get things back to normal
– Remove the bad, keep the good
* Eradicate the bug
– Remove malware
– Disable breached user accounts
– Fix vulnerabilities
* Recover the system
– Restore from backups
– Rebuild from scratch
– Replace compromised files
– Tighten down the perimeter
Lessons learned
Learn and improve
– No system is perfect
* Post-incident meeting
– Invite everyone affected by the incident
* Don’t wait too long
– Memories fade over time
– Some recommendations can be applied to
the next event
Answer the tough questions
What happened, exactly?
– Timestamp of the events
* How did your incident plans work?
– Did the process operate successfully?
* What would you do differently next time?
– Retrospective views provide context
* Which indicators would you watch next time?
– Different precursors may give you better alerts
Training for an incident
There’s limited on-the-job training when a security event occurs
– Be ready when an incident is identified
* Train the team prior to an incident
– Initial response
– Investigation plans
– Incident reporting
– And more
* This can be an expensive endeavor
– Especially with larger response teams
Exercising
Test yourselves before an actual event
– Scheduled update sessions (annual, semi-annual, etc.)
* Use well-defined rules of engagement
– Do not touch the production systems
* Very specific scenario
– Limited time to run the event
* Evaluate response
– Document and discuss
Tabletop exercises
Performing a full-scale disaster drill can be costly
– And time consuming
* Many of the logistics can be determined through analysis
– You don’t physically have to go through a disaster or drill
* Get key players together for a tabletop exercise
– Talk through a simulated disaster
Simulation
Test with a simulated event
– Phishing attack, password requests, data breaches
* Going phishing
– Create a phishing email attack
– Send to your actual user community
– See who bites
* Test internal security
– Did the phishing get past the filter?
* Test the users
– Who clicked?
– Additional training may be required
Root cause analysis
Determine the ultimate cause of an incident
– Find the root cause by asking “why”
* Create a set of conclusions regarding the incident
– Backed up by the facts
* Don’t get tunnel vision
– There can be more than a single root cause
* Mistakes happen
– The response to the mistake is the difference
Threat hunting
The constant game of cat and mouse
– Find the attacker before they find you
* Strategies are constantly changing
– Firewalls get stronger, so phishing gets better
* Intelligence data is reactive
– You can’t see the attack until it happens
* Speed up the reaction time
– Use technology to fight
Digital forensics
Collect and protect information relating to an intrusion
– Many different data sources and
protection mechanisms
* RFC 3227 - Guidelines for
– Evidence Collection and Archiving
– A good set of best practices
* Standard digital forensic process
– Acquisition, analysis, and reporting
* Must be detail oriented
– Take extensive notes
Legal hold
A legal technique to preserve relevant information
– Prepare for impending litigation
– Initiated by legal counsel
* Hold notification
– Custodians are instructed to preserve data
* Separate repository for electronically stored information
(ESI)
– Many different data sources and types
– Unique workflow and retention requirements
* Ongoing preservation
– Once notified, there’s an ongoing obligation to
preserve data
Chain of custody
Control evidence
– Maintain integrity
* Everyone who contacts the evidence
– Use hashes and digital signatures
– Avoid tampering
* Label and catalog everything
– Digitally tag all items for ongoing documentation
– Seal and store
Acquisition
Obtain the data
– Disk, RAM, firmware, OS files, etc.
* Some of the data may not be on a single system
– Servers, network data, firewall logs
* For virtual systems, get a snapshot
– Contains all files and information about a VM
* Look for any left-behind digital items
– Artifacts
– Log information, recycle bins, browser bookmarks,
saved logins, etc.
Reporting
Document the findings
– For Internal use, legal proceedings, etc.
* Summary information
– Overview of the security event
* Detailed explanation of data acquisition
– Step-by-step method of the process
* The findings
– An analysis of the data
* Conclusion
– Professional results, given the analysis
Preservation
Handling evidence
– Isolate and protect the data
– Analyze the data later without any alterations
* Manage the collection process
– Work from copies
– Manage the data collection from mobile devices
* Live collection has become an important skill
– Data may be encrypted or difficult to collect after
powering down
* Follow best practices to ensure admissibility of data in
court
– What happens now affects the future
E-discovery
Electronic discovery
– Collect, prepare, review, interpret, and produce
electronic documents
* E-discovery gathers data required by the legal process
– Does not generally involve analysis
– There’s no consideration of intent
* Works together with digital forensics
– The e-discovery process obtains a storage drive
– Data on the drive is smaller than expected
– Forensics experts determine that data was deleted and
attempt to recover the data
Security log files
Detailed security-related information
– Blocked and allowed traffic flows
– Exploit attempts
– Blocked URL categories
– DNS sinkhole traffic
* Critical security information
– Documentation of every traffic flow
– Summary of attack info
– Correlate with other logs
Firewall logs
Traffic flows through the firewall
– Source/destination IP, port numbers, disposition
* Next Generation Firewalls (NGFW)
– Logs the application used,
– URL filtering categories, anomalies and suspicious data
