Splunk : Enhancing Enterprise Security for Ransomware Detection

Ransomware isn't going away

Ransomware is a profitable business model for cyber criminals with 2016 payments closed at the billon dollar mark. According to a recent survey by IBM, nearly 70% of executives hit by ransomware have paid to get their data back. Those survey results do not include smaller organizations and consumers who are also paying to get their data back.

With the threat from ransomware growing, aside from prevention, detection is key to removing compromised devices from the network. Unfortunately, signature based detection alone will not catch everything, instead using a combination of hunting techniques within Splunk can enhance your security posture. In this blog, we will walk through adding the free ransomware intelligence feed from abuse.ch to Splunk Enterprise Security.

Requirements

• Internet Access for Splunk Enterprise Security Search Head
• Splunk Enterprise Security
• Knowledge of updating Splunk Configurations

Configuration

There are two paths forward, which will depend on the level of access you have to the enterprise security search head. Command line is the simplest option since you can copy paste the configuration from this page, while using the GUI will require you to manually input the data via Splunkweb.

The configuration file walthrough requires you to create a new inputs.conf file or add to an existing one in the SA-ThreatIntelligence app's local directory.

inputs.conf

[threatlist://ransomware_ip_blocklist] 
delim_regex = : 
description = abuse.ch Ransomware Blocklist 
disabled = false 
fields = ip:$1,description:Ransomware_ip_blocklist 
type = threatlist 
url = https://ransomwaretracker.abuse.ch/downloads/RW_IPBL.txt

Once completed, restart the splunkd service.

GUI Walkthrough:

Locate the Enterprise Security Configuration Page.

From the Enterprise Security Configuration page, select Threat Intelligence Downloads.

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Click new, and fill in the text fields on the resulting page with the same information:

Name: ransomware_ip_blocklist
Type: threatlist
Description: abuse.ch Ransomware Blocklist
URL: https://ransomwaretracker.abuse.ch/downloads/RW_IPBL.txt
Delimiting regular expression: :
Fields: ip:$1,description:Ransomware_ip_blocklist

Once configured, Enterprise Security will download the threat intelligence and begin alerting on any events found which match the threatlist. These can be reviewed and triaged as part of your workflow in the notable events page.
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