HydraSeven_loader

YARA-2025-0125 Medium general Active

New custom loader observed since September 2023

HydraSeven_loader.yar Valid Syntax

/*
 This Yara ruleset is under the GNU-GPLv2 license (http://www.gnu.org/licenses/gpl-2.0.html) and open to any user or organization, as long as you use it under this license.
*/
rule HydraSeven_loader
{
   meta:
        author = "Lucas Acha (http://www.lukeacha.com)"
        description = "New custom loader observed since September 2023"
        reference = "https://security5magics.blogspot.com/2023/10/interesting-customloader-observed-in.html" 
  strings:
      $mz = "MZ"
      $astring1 = "app.dll" ascii
      $wstring1 = "webView2" wide
      $wstring2 = /https?:\/\/.{1,35}\/main/ wide
      $d = "EmbeddedBrowserWebView.dll" wide
  condition:
    (($astring1 and $wstring1 and $wstring2) or ($d and $wstring2)) and $mz at 0 and filesize<1MB
}

Rule Metadata

author
Lucas Acha (http://www.lukeacha.com)
description
New custom loader observed since September 2023
reference
https://security5magics.blogspot.com/2023/10/interesting-customloader-observed-in.html

String Definitions

{"name":"$mz","value":"\"MZ\""}
{"name":"$astring1","value":"\"app.dll\" ascii"}
{"name":"$wstring1","value":"\"webView2\" wide"}
{"name":"$wstring2","value":"\/https?:\\\/\\\/.{1,35}\\\/main\/ wide"}
{"name":"$d","value":"\"EmbeddedBrowserWebView.dll\" wide"}

Threat Analysis

This YARA rule is designed to detect general threats.

Severity Level: Medium

The rule uses pattern matching to identify specific byte sequences, strings, or behavioral patterns associated with malicious activity.

Detection Capabilities

  • File-based detection for executables and documents
  • Memory scanning for running processes
  • Network traffic analysis support

Command Line Usage

# Scan a single file
yara HydraSeven_loader.yar /path/to/suspicious/file

# Scan a directory recursively
yara -r HydraSeven_loader.yar /path/to/directory/

# Scan with metadata output
yara -m HydraSeven_loader.yar target_file

# Scan process memory (Linux)
yara HydraSeven_loader.yar /proc/[pid]/exe

Integration Examples

Python (yara-python)

import yara
rules = yara.compile(filepath='HydraSeven_loader.yar')
matches = rules.match('/path/to/file')

ClamAV Integration

clamscan --yara-rules=HydraSeven_loader.yar /path/to/scan

Rule Information

YARA ID
YARA-2025-0125
Created
August 19, 2025
Last Updated
August 19, 2025
Last Imported
Never

Threat Intelligence

Risk Level Medium
Category general
Detection Confidence Analysis Pending
False Positive Rate Not Available
Last Seen in Wild No Data

Export Options