Detection rules › Sigma

Communication To Ngrok Tunneling Service Initiated

Severity
high
Author
Florian Roth (Nextron Systems)
Source
upstream

Detects an executable initiating a network connection to "ngrok" tunneling domains. Attackers were seen using this "ngrok" in order to store their second stage payloads and malware. While communication with such domains can be legitimate, often times is a sign of either data exfiltration by malicious actors or additional download.

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1090 Proxy, T1102 Web Service, T1568.002 Dynamic Resolution: Domain Generation Algorithms, T1572 Protocol Tunneling
ExfiltrationT1567 Exfiltration Over Web Service

Event coverage

ProviderEvent IDTitle
Sysmon3Network connection

Stages and Predicates

Stage 1: selection

or:
DestinationHostname|contains: tunnel.ap.ngrok.com
DestinationHostname|contains: tunnel.au.ngrok.com
DestinationHostname|contains: tunnel.eu.ngrok.com
DestinationHostname|contains: tunnel.in.ngrok.com
DestinationHostname|contains: tunnel.jp.ngrok.com
DestinationHostname|contains: tunnel.sa.ngrok.com
DestinationHostname|contains: tunnel.us.ngrok.com

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
DestinationHostnamematch
  • tunnel.ap.ngrok.com
  • tunnel.au.ngrok.com
  • tunnel.eu.ngrok.com
  • tunnel.in.ngrok.com
  • tunnel.jp.ngrok.com
  • tunnel.sa.ngrok.com
  • tunnel.us.ngrok.com