Incident Handling and Response to Insider Threats

Because an insider is an employee, is a trusted person and has access to various data, insider threats are major risks for organizations. Organizations are investing to prevent perimeter against external threat but focusing less on internal threats. This is the other factor that making insider threat more risky.

Attacks may come from different type of employees. These attackers may be system admins or managers who have authorized access to critical data, some unhappy or terminated employees, users who lost a device including sensitive data, or sending e-mail to incorrect receipints, or untrained personnel about security policies and best practices who subjected to social enginneering attacks.

All types of incidents require similar steps to respond. Here, we will try to explain the stages incident responders and actually whole organization must realize against an insider attack.

IH&R Steps for Insider Threats

EFFECTIVENESS OF INSIDER THREAT

Insider threat is a major risk because these kind of attack are very effective. It is difficult to detect and can go undetected for years. It is very easy to attack from inside since users have authorization to some data and systems, and can easily cover their actions by reaching to logs and deleting or modifying them. This makes also difficult to detect these type of attacks. Organizations need to monitor users’ behavior to detect and respond quickly.

As against all type of attacks, organizations need a well planned and regularly tested incident response plans to contain and eradicate insider attacks.

PREPERATION

The organizations must always be ready to an insider attack. Preparation stage is important to detect and respond these attacks.

  • Conduct security awareness trainings regularly to inform users against social engineering techniques. Insider attacks are not only done by malicious employees. Regular security awareness trainings will prevent your users with access to sensitive data from being used by malicious people.
  • Train users how to report any policy violation.
  • Classify organization’s data, identify the critical ones and apply need to know approach to reach to data.
  • Be sure all necessary logs are collected in SIEM.
  • Use privileged access management tools for storing passwords for all types of accounts reaching to critical data or production environment.
  • Make sure that terminated employees’ access rights are immediately removed both for logical and physical systems.
  • Deploy data loss prevention tools, but never trust that DLP will fully protect you. It is important to know the gaps of DLP tools to prevent data better. Make sure you read our post about DLP 🙂
  • Install NDR to detect abnormal behaviors of users. You can access our article explaining the importance of NDR against insider threat.
  • Install honeypot and honeytokens to lure attackers.
  • Segregate backup network from production or test networks and implement secure access methodologies to backup files.
  • Device control should be applied in the whole systems of the organizations. Users should not be allowed to use external storage.
  • Employees should sign a confidentiality and nondisclouse agreement bu Human Resources department.
  • Regularly and objective interviews and feedbacks from employees will help organization keep employees more peaceful.

DETECT AND ANALYZE

Indicators for insider threats are mostly abnormal behaviors of users. So, NDR with artifical intelligence technologies to detect anomaly in the network, UEBA, and Honeypot tools are critical to detect these type of attacks. The changes in network usage pattern may be indicator for ann insider threat.

It is important to collect logs in SIEM but in most cases, we saw in real life that huge amount of log data causes missing of malicious activity. It is more important to collect valuable logs and corralate them than collecting. Also, missing or modified logs may be indicator for insider threats. All log sources must be checked regularly to detect such an incident.

Accessing resources in unusual time and from unusal location may be indicator of insider threats. However, multiple login fail attempts may be used with these time and location information to cover unauthorized access attempts.

Users’ social media actions should be monitored. Unhappy and unmotivated users may try to post some unnecessary information about the organization.

Incident responders must analyze different logs from different sources after a suspicious activity has been reported. These logs may include IDS/IPS, proxy, NDR, EDR, DLP and email logs. They should check for a suspicious network connection and data transfers outside the network.

CONTAINMENT

For all types of attacks, containment is an indispensable stage for incident responders. It is fatally important to contain the source in question to prevent bad actors’ actions both laterally and outbound. Containment will minimizes the damages. Advanced EDR tools allows containment of such sources without having to be physically present near the source and incident handlers can still keep analyzing these sources while the threat could not be spread.

After detecting the malicious insider and containment, all privileges and credentials of this actor should be blocked, including e-mail and domain account and physical access cards.

ERADICATION

The organization should have an incident response plan and procedures to be able to move fast after an incident occurs. Eradication is also an important stage for incident handling and incident handlers should know in advance what to do in a case of insider attack by checking the policies and procedures.  However, eradication is not just CSIRT’s job. These are some processes all departments and emmployees must be involved. Malicious actor’s behaviors should be determined step by step and the preventive or detective control missings that allow her to do must be corrected. New security controls should be added and preperation stage should be reviewed again.

RECOVERY

The recovery stage must begin immediately after detecting, containing and eradicating the insider threat incident. If data is stolen and exfiltrated, incident responders should contact immmediately with the threat actor before selling or disclosuring it publicly.

Incident responders must be sure to gather ennough evidence for legal proceedings. This evidence will also help insurance processes.

In case the attacker placed malware or a backdoor inside the network, all systems should be checked carefully and all outbound connections should be checked against a C&C communication. A threat Hunting activity may be required.

If information is stolen and the stolen data is including user credentials, passwords should be changed whole over the organization.

POST-INCIDENT ACTIVITIES

This is one of the most important steps in incident Response. CSIRT should create a lessons learnt document after all incidents, this is also goes for insider threat incidents too. This lesson learnt documents will help organization preparing more effective to possible future incidents. In this stage, all the confusion caused by the incident will be gone and teams and responsible can identify what needs to be done for future readiness. Also, policies and procedures should be reviewed and changed if needed after lesson learnt works.

Also, all incidents and evidences should be documented properly to use in future.

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