analyzing-ransomware-payment-wallets

# Analyzing Ransomware Payment Wallets

## When to Use

- An organization has been hit by ransomware and the ransom note contains a Bitcoin or cryptocurrency wallet address that needs investigation
- Law enforcement or incident responders need to trace where ransom payments flowed after the victim paid
- Threat intelligence analysts are attributing ransomware campaigns by clustering payment infrastructure across incidents
- Investigators need to determine if a ransomware group is reusing wallet infrastructure across multiple victims
- Compliance or legal teams need evidence of fund flows for prosecution, sanctions enforcement, or insurance claims

**Do not use** this skill for live payment interception or to interact directly with ransomware operators. All analysis should be passive and read-only against public blockchain data.

## Prerequisites

- Python 3.8+ with `requests`, `json`, and `hashlib` libraries
- Access to blockchain explorer APIs (blockchain.com, WalletExplorer.com, Blockstream.info)
- Familiarity with Bitcoin transaction model (UTXOs, inputs, outputs, change addresses)
- Understanding of common obfuscation techniques (mixers, tumblers, peel chains, cross-chain swaps)
- Optional: Chainalysis Reactor license for enterprise-grade cluster analysis
- Optional: OXT.me for advanced transaction graph visualization

## Workflow

### Step 1: Extract Wallet Address from Ransom Note

Parse the ransom note to identify the payment address(es):

```
Common address formats:
  Bitcoin (P2PKH):   1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa  (starts with 1)
  Bitcoin (P2SH):    3J98t1WpEZ73CNmQviecrnyiWrnqRhWNLy  (starts with 3)
  Bitcoin (Bech32):  bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq (starts with bc1)
  Monero:            4... (95 characters, much harder to trace)
  Ethereum:          0x... (40 hex chars)
```

### Step 2: Query Blockchain Explorer for Transaction History

Retrieve all transactions associated with the wallet:

```python
import requests

def get_wallet_transactions(address):
    """Query blockchain.com API for address transactions."""
    url = f"https://blockchain.info/rawaddr/{address}"
    resp = requests.get(url, timeout=30)
    resp.raise_for_status()
    data = resp.json()
    return {
        "address": address,
        "n_tx": data.get("n_tx", 0),
        "total_received_satoshi": data.get("total_received", 0),
        "total_sent_satoshi": data.get("total_sent", 0),
        "final_balance_satoshi": data.get("final_balance", 0),
        "transactions": data.get("txs", []),
    }
```

### Step 3: Map Fund Flow and Identify Clusters

Trace outputs from the ransom wallet to downstream addresses:

```
Fund Flow Analysis:
━━━━━━━━━━━━━━━━━━
Victim Payment ──► Ransom Wallet ──► Consolidation Wallet
                                  ├─► Mixer/Tumbler Service
                                  ├─► Exchange Deposit Address
                                  └─► Peel Chain (sequential small outputs)

Key indicators:
  - Consolidation: Multiple ransom payments aggregated into one wallet
  - Peel chains: Sequential transactions with diminishing outputs
  - Mixer usage: Funds sent to known mixer addresses (Wasabi, Samourai, ChipMixer)
  - Exchange cashout: Deposits to known exchange wallets (Binance, Kraken hot wallets)
```

### Step 4: Cross-Reference with Known Wallet Databases

Check addresses against known ransomware infrastructure:

```python
# Check WalletExplorer for entity identification
def check_wallet_explorer(address):
    url = f"https://www.walletexplorer.com/api/1/address?address={address}&caller=research"
    resp = requests.get(url, timeout=30)
    data = resp.json()
    return {
        "wallet_id": data.get("wallet_id"),
        "label": data.get("label", "Unknown"),
        "is_exchange": data.get("is_exchange", False),
    }
```

### Step 5: Generate Attribution Report

Compile findings into a structured intelligence report:

```
RANSOMWARE WALLET ANALYSIS REPORT
====================================
Ransom Address:      bc1q...xyz
Family Attribution:  LockBit 3.0 (based on ransom note format)
Total Received:      4.25 BTC ($178,500 at time of payment)
Total Sent:          4.25 BTC (wallet fully drained)
Number of Payments:  3 (likely 3 separate victims)

FUND FLOW:
  Payment 1: 1.5 BTC → Consolidation wallet → Binance deposit
  Payment 2: 1.0 BTC → Wasabi Mixer → Unknown
  Payment 3: 1.75 BTC → Peel chain (12 hops) → OKX deposit

CLUSTER ANALYSIS:
  Related wallets: 47 addresses identified in same cluster
  Total cluster volume: 156.3 BTC ($6.5M USD)
  First activity: 2024-01-15
  Last activity: 2024-09-22
```

## Verification

- Confirm wallet address format is valid before querying APIs
- Cross-reference transaction timestamps with known incident timelines
- Validate cluster associations by checking common-input-ownership heuristic
- Compare findings against OFAC SDN list for sanctioned addresses
- Verify exchange attribution against multiple sources (WalletExplorer, OXT, Chainalysis)

## Key Concepts

| Term | Definition |
|------|------------|
| **UTXO** | Unspent Transaction Output; the fundamental unit of Bitcoin that tracks ownership through a chain of transactions |
| **Cluster Analysis** | Grouping multiple Bitcoin addresses believed to be controlled by the same entity using common-input-ownership and change-address heuristics |
| **Peel Chain** | A laundering pattern where funds are sent through many sequential transactions, each peeling off a small amount to a new address |
| **CoinJoin/Mixer** | Privacy techniques that combine multiple users' transactions to obscure the link between sender and receiver |
| **Common Input Ownership** | Heuristic that assumes all inputs to a single transaction are controlled by the same entity |

## Tools & Systems

- **Chainalysis Reactor**: Enterprise blockchain investigation platform with entity attribution and cross-chain tracing
- **WalletExplorer**: Free tool that clusters Bitcoin addresses and labels known services (exchanges, mixers, markets)
- **OXT.me**: Advanced Bitcoin transaction visualization with UTXO graph analysis
- **Blockstream.info**: Open-source Bitcoin block explorer with full API access
- **blockchain.com API**: Free API for querying Bitcoin address balances and transaction histories
- **OFAC SDN List**: U.S. Treasury sanctioned address list for compliance checking