Angler Exploit Kit Detection

Hunt Hypothesis

Angler Exploit Kit activity is detected through unusual network traffic patterns and suspicious file execution behaviors indicative of exploit kit deployment. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate potential compromise from Angler, which is known for delivering malware and ransomware payloads.

YARA Rule

rule angler_jar : EK
{
meta:
   author = "Josh Berry"
   date = "2016-06-26"
   description = "Angler Exploit Kit Detection"
   hash0 = "3de78737b728811af38ea780de5f5ed7"
   sample_filetype = "unknown"
   yaragenerator = "https://github.com/Xen0ph0n/YaraGenerator"
strings:
   $string0 = "myftysbrth"
   $string1 = "classPK"
   $string2 = "8aoadN"
   $string3 = "j5/_<F"
   $string4 = "FXPreloader.class"
   $string5 = "V4w\\K,"
   $string6 = "W\\Vr2a"
   $string7 = "META-INF/MANIFEST.MF"
   $string8 = "Na8$NS"
   $string9 = "_YJjB'"
condition:
   9 of them
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

• Microsoft Defender for Endpoint — Custom indicators / advanced hunting
• Email Gateway — Attachment scanning
• File Share Monitoring — Periodic scanning of shared drives
• YARA CLI — Manual threat hunting on endpoints

This rule contains 10 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: Scheduled system update via Windows Update
  Filter/Exclusion: process.parent_process != "svchost.exe" OR process.name != "wusa.exe"

• Scenario: Legitimate use of Metasploit for penetration testing
  Filter/Exclusion: process.name != "msfconsole.exe" OR process.parent_process != "msfconsole.exe"

• Scenario: Admin performing a PowerShell-based system cleanup
  Filter/Exclusion: process.name != "powershell.exe" OR process.parent_process != "explorer.exe"

• Scenario: Automated backup job using Veeam Backup & Replication
  Filter/Exclusion: process.name != "vmrun.exe" OR process.parent_process != "veeam.exe"

• Scenario: User running a legitimate exploit mitigation tool like Cisco Talos Intelligence
  Filter/Exclusion: process.name != "talos-intel.exe" OR process.parent_process != "explorer.exe"