Analyzing Malware Family Relationships With Malpedia

Analyzing Malware Family Relationships with Malpedia

Overview

Malpedia is a collaborative platform maintained by Fraunhofer FKIE that catalogs malware families with their aliases, YARA rules, threat actor associations, and reference reports. With over 2,600 malware families documented, it serves as the definitive resource for understanding malware lineages, tracking variant evolution, and linking malware to specific threat groups. This skill covers querying the Malpedia API, mapping malware family relationships, extracting YARA rules for detection, and building intelligence on malware ecosystems used by adversaries.

When to Use

• When investigating security incidents that require analyzing malware family relationships with malpedia
• When building detection rules or threat hunting queries for this domain
• When SOC analysts need structured procedures for this analysis type
• When validating security monitoring coverage for related attack techniques

Detection Gaps & Validation

• Alias collisions & naming drift: the same code gets different platform.family entries across vendors, and umbrella names (e.g., "Cobalt Strike", commodity loaders) lump unrelated activity together. Resolve via Malpedia alt_names before asserting two reports describe the same family.
• Shared-tooling over-attribution: find_shared_tooling() overlap on win.cobalt_strike/win.qakbot reflects a commodity ecosystem, not a shared operator -- red-team and criminal use of the same family is the norm. Do not infer actor linkage from commodity families alone.
• YARA coverage gaps: community rules in Malpedia vary in quality; broad string rules over-match packed/UPX samples and miss new variants.
• Hardcoded chains: the known_chains map is a static snapshot -- loader->payload relationships (Emotet->TrickBot->Ryuk) shift as crews rebrand.

To validate: compile the extracted YARA set with yara-python against a labeled corpus of known-family samples plus a benign set, and measure both detection and false-positive rates -- a rule that flags clean binaries is worse than none. Confirm a family match with representative sample hashes from Malpedia rather than the family name alone, and verify apitoken auth and 404 handling so an empty result is not mistaken for "no relationship."

Prerequisites

• Python 3.9+ with requests, yara-python, stix2 libraries
• Malpedia API key (register at https://malpedia.caad.fkie.fraunhofer.de/)
• Understanding of malware classification and naming conventions
• Familiarity with YARA rule syntax for detection
• Access to malware samples for validation (optional)

Key Concepts

Malpedia Data Model

Malpedia organizes malware into Families (e.g., "win.cobalt_strike"), each containing: aliases (vendor-specific names like "Beacon", "CobaltStrike"), YARA rules (community and vendor-contributed), actor associations (threat groups using the family), reference reports (CTI reports documenting the family), and sample hashes (representative samples for each variant).

Malware Family Naming

Malpedia uses the format platform.family_name (e.g., win.emotet, elf.mirai, apk.flubot). Platforms include win (Windows), elf (Linux), apk (Android), osx (macOS), and py (Python). This standardized naming resolves the "many names" problem where different vendors assign different names to the same malware.

Family Relationships

Malware families have relationships including: parent-child (code reuse, forks), loader-payload (Emotet loads TrickBot loads Ryuk), shared authorship (same threat actor develops multiple tools), and infrastructure sharing (common C2 frameworks).

Workflow

Step 1: Query Malpedia API for Malware Families

import requests
import json
from collections import defaultdict

class MalpediaClient:
    BASE_URL = "https://malpedia.caad.fkie.fraunhofer.de/api"

    def __init__(self, api_key):
        self.headers = {"Authorization": f"apitoken {api_key}"}

    def get_family_list(self):
        """Get list of all malware families."""
        resp = requests.get(f"{self.BASE_URL}/list/families",
                           headers=self.headers, timeout=30)
        if resp.status_code == 200:
            families = resp.json()
            print(f"[+] Malpedia: {len(families)} malware families")
            return families
        return {}

    def get_family_info(self, family_name):
        """Get detailed information about a malware family."""
        resp = requests.get(f"{self.BASE_URL}/get/family/{family_name}",
                           headers=self.headers, timeout=30)
        if resp.status_code == 200:
            info = resp.json()
            print(f"[+] Family: {family_name}")
            print(f"    Aliases: {info.get('alt_names', [])}")
            print(f"    Actors: {[a.get('value', '') for a in info.get('attribution', [])]}")
            print(f"    URLs: {len(info.get('urls', []))} references")
            return info
        print(f"[-] Family not found: {family_name}")
        return None

    def get_family_yara(self, family_name):
        """Get YARA rules for a malware family."""
        resp = requests.get(f"{self.BASE_URL}/get/yara/{family_name}",
                           headers=self.headers, timeout=30)
        if resp.status_code == 200:
            rules = resp.json()
            rule_count = sum(len(v) for v in rules.values()) if isinstance(rules, dict) else 0
            print(f"[+] YARA rules for {family_name}: {rule_count} rules")
            return rules
        return {}

    def get_actor_families(self, actor_name):
        """Get malware families associated with a threat actor."""
        resp = requests.get(f"{self.BASE_URL}/get/actor/{actor_name}",
                           headers=self.headers, timeout=30)
        if resp.status_code == 200:
            data = resp.json()
            families = data.get("families", {})
            print(f"[+] {actor_name}: {len(families)} malware families")
            return data
        return {}

    def search_families(self, keyword):
        """Search families by keyword."""
        all_families = self.get_family_list()
        matches = {
            name: info for name, info in all_families.items()
            if keyword.lower() in name.lower()
            or keyword.lower() in str(info.get("alt_names", [])).lower()
        }
        print(f"[+] Search '{keyword}': {len(matches)} matches")
        return matches

client = MalpediaClient("YOUR_MALPEDIA_API_KEY")
families = client.get_family_list()
emotet_info = client.get_family_info("win.emotet")

Step 2: Map Malware Family Relationships

class MalwareFamilyMapper:
    def __init__(self, malpedia_client):
        self.client = malpedia_client
        self.relationship_graph = defaultdict(list)

    def map_actor_ecosystem(self, actor_name):
        """Map the malware ecosystem used by a threat actor."""
        actor_data = self.client.get_actor_families(actor_name)
        families = actor_data.get("families", {})

        ecosystem = {
            "actor": actor_name,
            "families": [],
            "family_count": len(families),
        }

        for family_name in families:
            info = self.client.get_family_info(family_name)
            if info:
                ecosystem["families"].append({
                    "name": family_name,
                    "aliases": info.get("alt_names", []),
                    "description": info.get("description", "")[:200],
                    "shared_actors": [
                        a.get("value", "")
                        for a in info.get("attribution", [])
                    ],
                    "reference_count": len(info.get("urls", [])),
                })

        print(f"\n=== {actor_name} Malware Ecosystem ===")
        for fam in ecosystem["families"]:
            shared = [a for a in fam["shared_actors"] if a != actor_name]
            print(f"  {fam['name']}")
            print(f"    Aliases: {fam['aliases'][:5]}")
            if shared:
                print(f"    Also used by: {shared}")

        return ecosystem

    def find_shared_tooling(self, actor_names):
        """Find malware families shared between threat actors."""
        actor_families = {}
        for actor in actor_names:
            data = self.client.get_actor_families(actor)
            actor_families[actor] = set(data.get("families", {}).keys())

        # Find overlaps
        shared = {}
        for i, actor1 in enumerate(actor_names):
            for actor2 in actor_names[i+1:]:
                common = actor_families[actor1] & actor_families[actor2]
                if common:
                    shared[f"{actor1} <-> {actor2}"] = sorted(common)

        print(f"\n=== Shared Tooling Analysis ===")
        for pair, families in shared.items():
            print(f"  {pair}: {len(families)} shared families")
            for f in families[:5]:
                print(f"    - {f}")

        return shared

    def build_loader_payload_chain(self, family_name):
        """Build the loader-payload delivery chain for a family."""
        info = self.client.get_family_info(family_name)
        if not info:
            return {}

        chain = {
            "family": family_name,
            "description": info.get("description", ""),
            "known_loaders": [],
            "known_payloads": [],
        }

        # Common known delivery chains
        known_chains = {
            "win.emotet": {"loaders": ["email/macro"], "payloads": ["win.trickbot", "win.qakbot", "win.cobalt_strike"]},
            "win.trickbot": {"loaders": ["win.emotet"], "payloads": ["win.ryuk", "win.conti", "win.cobalt_strike"]},
            "win.qakbot": {"loaders": ["email/macro", "win.emotet"], "payloads": ["win.cobalt_strike", "win.blackbasta"]},
            "win.cobalt_strike": {"loaders": ["win.emotet", "win.trickbot", "win.qakbot"], "payloads": ["ransomware"]},
        }

        if family_name in known_chains:
            chain["known_loaders"] = known_chains[family_name]["loaders"]
            chain["known_payloads"] = known_chains[family_name]["payloads"]

        return chain

mapper = MalwareFamilyMapper(client)
ecosystem = mapper.map_actor_ecosystem("Wizard Spider")
shared = mapper.find_shared_tooling(["Wizard Spider", "FIN7", "Lazarus Group"])
chain = mapper.build_loader_payload_chain("win.emotet")

Step 3: Extract and Compile YARA Rules

def compile_yara_ruleset(client, family_names, output_file="malware_yara_rules.yar"):
    """Compile YARA rules for multiple malware families."""
    all_rules = []
    for family in family_names:
        yara_data = client.get_family_yara(family)
        if isinstance(yara_data, dict):
            for source, rules in yara_data.items():
                if isinstance(rules, list):
                    for rule in rules:
                        all_rules.append(f"// Source: {source} - Family: {family}\n{rule}")
                elif isinstance(rules, str):
                    all_rules.append(f"// Source: {source} - Family: {family}\n{rules}")

    with open(output_file, "w") as f:
        f.write(f"// Malpedia YARA Rules - {len(all_rules)} rules\n")
        f.write(f"// Families: {', '.join(family_names)}\n\n")
        for rule in all_rules:
            f.write(rule + "\n\n")

    print(f"[+] Compiled {len(all_rules)} YARA rules to {output_file}")
    return all_rules

compile_yara_ruleset(client, ["win.emotet", "win.trickbot", "win.cobalt_strike"])

Validation Criteria

• Malpedia API queried successfully for malware families
• Family information retrieved with aliases, actors, and references
• Actor-family relationships mapped correctly
• Shared tooling between actors identified
• YARA rules extracted and compiled for detection
• Loader-payload chains documented for threat intelligence

References

• Malpedia Platform
• Malpedia API Documentation
• Malpedia Research Paper
• YARA Rules Project
• malwoverview Multi-Platform Tool
• CyberAtlas: Malpedia Integration