Backdoor_WebShell_asp

YARA-2019-0033 High general Active

Detect ASPXSpy

Backdoor_WebShell_asp.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 Backdoor_WebShell_asp : ASPXSpy
{
    meta:
    description= "Detect ASPXSpy"
    author = "xylitol@temari.fr"
    date = "2019-02-26"
    // May only the challenge guide you
    strings:
    $string1 = "CmdShell" wide ascii
    $string2 = "ADSViewer" wide ascii
    $string3 = "ASPXSpy.Bin" wide ascii
    $string4 = "PortScan" wide ascii
    $plugin = "Test.AspxSpyPlugins" wide ascii
 
    condition:
    3 of ($string*) or $plugin
}

Rule Metadata

description
Detect ASPXSpy
author
xylitol@temari.fr
date
2019-02-26

Tags

ASPXSpy

String Definitions

{"name":"$string1","value":"\"CmdShell\" wide ascii"}
{"name":"$string2","value":"\"ADSViewer\" wide ascii"}
{"name":"$string3","value":"\"ASPXSpy.Bin\" wide ascii"}
{"name":"$string4","value":"\"PortScan\" wide ascii"}
{"name":"$plugin","value":"\"Test.AspxSpyPlugins\" wide ascii"}

Threat Analysis

This YARA rule is designed to detect general threats.

Severity Level: High

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 Backdoor_WebShell_asp.yar /path/to/suspicious/file

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

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

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

Integration Examples

Python (yara-python)

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

ClamAV Integration

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

Rule Information

YARA ID
YARA-2019-0033
Created
August 19, 2025
Last Updated
August 19, 2025
Last Imported
Never

Threat Intelligence

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

Export Options