LoFP / web activity that occurs rarely in small quantities can trigger this alert. possible examples are browsing technical support or vendor urls that are used very sparsely. a user who visits a new and unique web destination may trigger this alert when the activity is sparse. web applications that generate urls unique to a transaction may trigger this when they are used sparsely. web domains can be excluded in cases such as these.

Techniques

• T1071

Sample rules

Unusual Web Request

• source: elastic
• technicques:
  • T1071

Description

A machine learning job detected a rare and unusual URL that indicates unusual web browsing activity. This can be due to initial access, persistence, command-and-control, or exfiltration activity. For example, in a strategic web compromise or watering hole attack, when a trusted website is compromised to target a particular sector or organization, targeted users may receive emails with uncommon URLs for trusted websites. These URLs can be used to download and run a payload. When malware is already running, it may send requests to uncommon URLs on trusted websites the malware uses for command-and-control communication. When rare URLs are observed being requested for a local web server by a remote source, these can be due to web scanning, enumeration or attack traffic, or they can be due to bots and web scrapers which are part of common Internet background traffic.

Detection logic

Unusual Network Destination Domain Name

• source: elastic
• technicques:

Description

A machine learning job detected an unusual network destination domain name. This can be due to initial access, persistence, command-and-control, or exfiltration activity. For example, when a user clicks on a link in a phishing email or opens a malicious document, a request may be sent to download and run a payload from an uncommon web server name. When malware is already running, it may send requests to an uncommon DNS domain the malware uses for command-and-control communication.

Detection logic