Unmasking AVrecon: A Guide to Proactive Threat Hunting

In the ever-evolving landscape of cybersecurity, threat actors continue to develop new and sophisticated tools to bypass security measures. One such tool, AVrecon, has emerged as a stealthy and evasive reconnaissance malware, designed to gather information about an organization’s security solutions and defenses. To counter this emerging threat, proactive threat hunting becomes essential to identify and neutralize AVrecon before it can inflict damage. In this blog, we will embark on a journey of threat hunting for AVrecon, featuring real-world examples, Splunk queries, and YARA rules to empower organizations in defending against this reconnaissance adversary.

AVrecon is a reconnaissance malware used by threat actors to gather information about an organization’s antivirus and security solutions. By doing so, the attackers can customize their attack vectors and avoid detection. AVrecon often enters a system through phishing emails, malicious downloads, or exploit kits. Once inside, it stealthily collects data on installed security tools, processes, and configurations.

Let’s explore practical threat hunting examples to detect and respond to AVrecon activities:

Example 1: Unusual Network Traffic
Hunt for unusual outbound connections from internal systems.

index=network earliest=-1d | stats count by src_ip, dest_ip

Investigate any significant spikes in outbound connections to suspicious or unknown IP addresses.

Example 2: Suspicious Process Activity
Monitor for unusual process execution on endpoints.

index=main sourcetype=”WinEventLog:Security” EventCode=4688 earliest=-1w

Look for processes launched from uncommon locations or with suspicious names.

YARA rules provide a powerful way to create custom signatures for detecting AVrecon malware. Let’s create a YARA rule for AVrecon:

rule AVrecon_Malware {
meta:
description = “Detects AVrecon reconnaissance malware”
strings:
$magic = { 4D 5A } // MZ (DOS/Windows executable)
$pattern = “AVrecon” // Unique string indicative of AVrecon
condition:
$magic at 0 and $pattern
}

Leverage Splunk for endpoint and network monitoring to detect potential AVrecon infections:

# Endpoint Activity Monitoring
index=main sourcetype=”WinEventLog:Security” EventCode=4688
| search New_Process_Name=”*.exe” OR New_Process_Name=”*.dll”

# Network Activity Monitoring
index=network earliest=-1w
| rex field=_raw “Host=(?<dest_host>[^\s]+)”
| rex field=_raw “User_Agent=(?<user_agent>[^\s]+)”
| search dest_host=”*.onion” OR user_agent=”AVrecon”

Threat hunting is an indispensable practice to stay ahead of the stealthy and reconnaissance-focused AVrecon malware. By employing Splunk queries and YARA rules, organizations can enhance their detection capabilities, identify suspicious activities, and respond swiftly to AVrecon threats. Continuous monitoring and collaboration with the cybersecurity community are essential to stay ahead of AVrecon’s rapidly evolving tactics. Implementing these strategies will fortify your organization’s cybersecurity defenses, ensuring resilience against AVrecon and other reconnaissance malware. Remember, a vigilant and proactive approach to threat hunting is the key to unmasking AVrecon and safeguarding your network from its reconnaissance intentions. Happy hunting!

(Note: The examples provided in this blog are intended for illustrative purposes only and may require customization based on the specific environment and requirements of individual organizations.)