Friday, January 5, 2018

Cybersecurity's Biggest Mistake - The Daystrom Syndrome

I've been very fortunate to be part of the design team of the Virginia Cyber Range (www.virginiacyberrange.org). The range is designed to a) be a course repository (full course material,  individual course modules, individual lab exercises) for NSA CAE schools in VA and K-12 school in VA and b) provide an environment to run these classes and exercises from any location in the world. I'll have more on that in a later blog. One of the unexpected surprises in the project is the enthusiastic adoption of the Range by the K-12 schools. K-12 teachers were caught in the middle of a number of competing worlds:
  • Federal and state political pressure on school systems to include cybersecurity concepts in K-12 classes
  • School system pressure on K-12 schools to do the same
  • Local (principal) pressure on local faculty to develop these courses
  • Teachers are unable to create these environments because of school system and local IT resistance to build the environment needed to teach these classes.
That last bullet item turned out to be the major stumbling block in implementing these education programs. Why? As you probably know, local school systems have tightly regulated, locked down and restricted access to the internet from their school networks. Some of the reasons have to do with parental concern on questionable material/people on the net getting access to K-12 students; general concerns of the school IT staff to protect systems and data from unauthorized access. I suspect the real reason is a lack of funding to increase IT staff sizes  and provide training to said staff. When you're 1 admin for 1000 machines, you're not going to allow special cases simply because you don't have the cycles to provide the required support.

I came from the sysadmin world and remember the "prime directive" of sysadmins: "Keep the systems running at all costs". This directive, while noble, has caused more security headaches over the past 25 years. Simple things like patching OS, applications and hardware for security issues run into the sysadmin prime directive which resulted in security vulnerabilities not being corrected in a timely manner.

This reminds me of the "Ultimate Computer" episode of Star Trek (TOS). The Enterprise was fitted with the new M5 computer which automated the ship's handling, offensive and defensive capabilities. When things went south quickly because the M5 started behaving in a dangerous manner, Dr. Daystrom was blind to what the machines was doing because of his loyalty to a particular train of thought ("You don't shut a child off when it makes a mistake. M-5 is growing, learning."
"Learning to kill." "To defend itself. It's quite a different thing.")

 Sysadmins were infected with the "Daystrom syndrome" where we became so involved (enamored?) with our technology that we lost sight of the real goal of our technology: to allow people to use the technology in a meaningful way to themselves and to business.  Some examples of this Daystrom Syndrome variant include:
  • making systems harder to use for the sake of "security" of the system
  • restricting how users can access information that is "questionable" to the IT person but not the user. We're not talking about porn here. We're talking about using the Internet as a research tool to get software, algorithms, etc. that make our business more efficient and how this behavior is restricted by IT because of security issues.
  • not patching systems because that would required them being unavailable for a period of time. This downtime violates the 24x7 availability rule that is one of the governing things that sets sysadmin behavior.
  • Anything that causes the user to say "IT won't let me do this"
  • Anything that causes sysadmins to say " users will wreck our security, availability, stability".
Sysadmins and their upper mgt have forgotten the prime reason why IT exists in business is to allow the business to make more money (grow the business) by making business processes more efficient.

Let me come back to the Range and K-12 scenario. The conundrum is the K-12 teachers need to build machines that can connect to the net and be able to be configured, modified by teachers and students. Let's also face the fact that most school IT suffers from low budgets and the IT staff/machine ratio is frighteningly high. These factors combined with the Daystrom sysndrome means the K-12 teachers are told they can't use the school systems or net to build these cybersecurity classes. The Range provides an environment that allows teachers to actually create a space for their classes without IT interference. The school IT just have to allow web access to the Range. Unfortunately, this sometimes is easier said than done.

This brings me back to my premise - IT has created a worse security problem than the one they were trying to solve by imposing unnecessary restrictions on user behavior thereby preventing them from doing their jobs which encourages them to bypass these restrictions.

It's time for us to rethink the model.

Monday, June 5, 2017

Assume They're In Your Network Already



1       Background


Traditional network border defense strategies have focused on a) keeping intruders out of a network b) protecting internal devices from compromise. Historically, sites have implemented their security strategy from the border inward rather than from the endpoint outward.

895,871,345 records have been breached as of 2/21/2016 according to www.privacyrights.org. Data from this and similar sites suggests the traditional border network defense model has failed as a data protection strategy.

Border firewalls are not effective "protection" devices. They are, however, excellent "detection" devices. Why? Firewalls always have to let data pass through them. Wireless networks negate the effectiveness of a "border" firewall  by forcing the network border to be at the endpoint. Whitelisting outbound traffic is a challenge because most sites are now hosted by companies like Akemai which host thousands of sites. However, firewalls log packet traffic and this information is valuable in network forensics.

Continuous monitoring (CM) is an effective strategy to detect and interrupt data exfiltration.  Seth Misenar and Eric Conrad [1] list 4 points that show why Continuous Monitoring (CM) is a better strategy for detecting, preventing and/or interrupting data exfiltration. The 4 points are:

1.     Highly portable devices don’t benefit from the traditional border network defense model.
2.     Client-side exploitation significantly decreases the effectiveness of traditional network defense architectures.
3.     Lateral movement inside your network after a compromise increases the likelihood of endpoint exploitation.
4.     Endpoints must be able to defend themselves and aid in detection.

Monitoring outbound traffic allows a site to use CM techniques to determine if a data breach has happened. Unauthorized data transfers are rarely detected by traditional IDS, IPS or firewalls because intellectual property isn’t just the standard social security, credit card, driver license, bank/debit account numbers.  Intellectual property is harder to classify because the “sensitive” data elements are not the traditional items that DLP solutions can find. Netflow monitoring techniques can be used to detect anomalous traffic patterns.

2       Hacker Attack Strategy

When hackers attack a site, they have 3 primary goals:
  • ·        Compromise the endpoint and search for data that can be stolen. 
  • ·        Maintain control of the endpoint so it can be used to attack internal and external systems.
  • ·        Be able to destroy the system to eliminate evidence of a compromise if discovered.
Hackers have adapted to inbound blocks by tricking internal users into initiating an outbound connection to the malware site. For example, the infostealer malware class searches the target system for sensitive data such as SSN, CCN, bank or debit account information, builds a list of files containing these data, phones “home” to let the hacker know it has data ready for exfiltration.
A compromised machine has to communicate back to the hacker when an attack is successful. If defenders interrupt the communications/control channel established, a data exfiltration is prevented or interrupted. This also prevents the hackers from issuing a “self destruct” command to cover their tracks.

3       Continuous Monitoring Defense

Prevention eventually fails but detection and containment are forever. CM assumes the attackers are inside your network and provides the data to find them. The defenders' best chance for containing the attack lies in interrupting hacker goal #2. Here’s how CM can help determine if a data breach of personally identifiable information (PII) has occurred.

1. The general security strategy should be "protect (encrypt) sensitive data regardless of location." Protecting devices is obviously important, however, if the sensitive data is protected then the probability of a data breach is reduced.

2. Monitoring outbound traffic can detect anomalous outbound transmissions. If a system is compromised, we ask if there was any sensitive data on the device.
a. No. Use logs (syslog, eventlog, net flow, sensor, firewall, IDS, DLP) to isolate the compromised host and if any external communication has happened. Reinstall/reimage compromised host. Go to step 1.
b. Yes. Run PII search tools like IdentityFinder, Find_SSN to find out how many records were potentially exposed. If the data files were encrypted, the chances of a data breach are minimal, go to step 2a. If PII was in the clear, determine how many unique records were in the file. Go to step 3. 

3. Determine if sensitive data file(s) were exfiltrated from the net. Use network forensics to determine:
a) when was the earliest communication between the attacker and the compromised endpoint. This helps us define the window of exposure.
b) if other internal hosts were accessed from this compromised host. This helps us define the extent of the attack.
c) the probability of sensitive data breach occurring by examining netflow data to and from the compromised host.

Historical network data is used to answer the above questions. That data comes from various sensors each fulfilling a role in CM. The biggest advantage defenders have is the ability to monitor their network traffic. A system whose logs have been wiped can still be monitored by examining network traffic.

4       A Continuous Monitoring Example

How do we detect a suspicious exfiltration? First, you have to establish a “traffic” baseline to see what is considered “normal” traffic.  Baselining provides you with the answer to “where do my organization’s packets go? For example, the chart shown in Figure 1 shows the countries that send and receive packets from a network in a month. The blue bar shows packets that enter the network from a country and the red bar shows packets that leave the network for a particular country.  Once you profile the inbound/outbound traffic, you can do a detailed analysis of the traffic.
Packet traffic within the United States is shown at the bottom of the figure. A possible explanation is the majority of this traffic goes to external search engines. For example, a search engine query for “Randy Marchany” sends a relatively short packet stream to a search engine. The results of the search are usually much greater in size than the original query. Obviously, not all traffic is web based but having this data allows you to do a detailed analysis of your network traffic.



Figure 1. Inbound/outbound network traffic by country

Figure 2 shows a different pattern. It shows a traffic pattern of a large amount of data packets leaving the network for China, Great Britain and Brazil. This pattern doesn’t confirm an exfiltration is happening but we certainly have reason to investigate this traffic further. The analysis confirmed an exfiltration was happening. The incident response team was able to take steps to contain and interrupt the data transfer.



Figure 2. Inbound/outbound traffic by country with anomaly

5       Summary

The traditional network border defense strategy has failed to prevent data breaches. It's time to change our defensive posture from inbound-centric to outbound-centric. Continuous Monitoring allows us to determine if a data exfiltration has happened. CM and network forensics are the difference between a small, internal breach and a major disaster.

 Some good reference books on this topic are "Extrusion Detection: Security Monitoring for Internal Intrusions" by Richard Bejtlich, "Network Forensics"  by Sherri Davidoff and Jonathan Ham, "Applied Network Security Monitoring" by Chris Sanders and Jason Smith.