Crypto Wallet Security

Cryptocurrency Wallet Security

Here's a comprehensive crypto wallet security assessment methodology from an attacker's perspective. This article / guide is on crypto wallet security.

Crypto Wallet Security Assessment Methodology

Phase 1: Information Gathering & Reconnaissance

Identify wallet type:

• Custodial (exchange-hosted — Coinbase, Binance) vs. Non-custodial (self-hosted — Electrum, MetaMask, Ledger)

• Hot (online, connected) vs. Cold (offline, air-gapped)

• Software (desktop/mobile/browser) vs. Hardware (dedicated device)

Tooling fingerprinting:

• What wallet software and version?

• Which BIP standards implemented? (BIP32/39/44/49/84/86)

• Backend infrastructure (Infura, Alchemy, self-hosted node?)

• Mobile: is Secure Enclave / TEE used? Keychain / Keystore implementation?

• Desktop: how is the seed stored? Encrypted JSON? Plaintext memory?

Phase 2: Attack Surface Categories

2A — Seed Phrase / Private Key Extraction

Attack Vector	Technique
Memory dumping	Process dump of wallet app while unlocked. Search for BIP39 words, entropy, or raw private keys in heap. Tools: procdump, volatility, WinDbg
Clipboard hijacking	Malware monitoring clipboard for copied addresses, seed phrases. Pastejacking — swap destination address on copy
TEMPEST / Van Eck phreaking	Electromagnetic emissions from screen/keyboard during wallet typing. Hardware attack, but demonstrated against offline wallets
Side-channel timing	Timing analysis of signature operations to recover ECDSA nonces
Cold boot attack	Reboot machine without powering off; dump RAM for keys (works best on unencrypted systems)
Swap file / hibernation file	Keys may be paged to disk. Extract from pagefile.sys, hiberfil.sys, /var/vm/swapfile
Keylogger / screen capture	Capture seed phrase entry during wallet creation or restore

2B — Network & Communication Attacks

Attack Vector	Technique
RPC endpoint exposure	Wallet software often exposes JSON-RPC on localhost. If misconfigured (e.g., rpcbind=0.0.0.0), external access possible. Default ports: 8332 (Bitcoin Core), 8545 (Ethereum)
Man-in-the-middle	Unencrypted RPC, HTTP-based sync, or DNS spoofing of blockchain data feeds
Sybil / Eclipse attack	Isolate wallet node from honest peers; feed fabricated blockchain data to manipulate balances or double-spend
Blockchain data poisoning	Malicious inscriptions in transaction data executed when wallet parses tx history
Infura / RPC provider compromise	Wallets using default providers (Infura, Alchemy) — provider can log IPs, correlate addresses, or serve malicious data

2C — Application Layer Vulnerabilities

Attack Vector	Technique
Dependency chain	Audit package.json, requirements.txt, Cargo.lock — known CVEs in web3.js, ethers.js, bitcoinj, libsecp256k1
RNG weakness	Check if wallet uses Math.random() (predictable) vs. CSPRNG. The Android Bitcoin Wallet (2013) bug — 50 BTC lost due to weak RNG
Replay attacks	If nonce reuse occurs across chains (ETH + ETH Classic), signatures can be replayed
Transaction malleability	Modify raw tx before broadcast (BTC case: Mt. Gox exploited this)
Reused address derivation	HD wallet fingerprinting — if a parent public key is leaked, all child addresses can be discovered
Proxy re-encryption flaws	Browser extension wallets (MetaMask) — cross-origin communication, window.ethereum injection, malicious dApp draining

2D — Hardware Wallet Specific

Attack Vector	Technique
Firmware downgrade	Flash older firmware with known vulnerabilities
Supply chain	Device tampered before delivery — compromised RNG, pre-loaded keys
Side-channel (power/EM)	SPA/DPA on ECDSA signing — recover key from power consumption traces
Chip glitching	Voltage or clock glitching to bypass PIN verification or read protected memory
Debug interface	JTAG/SWD exposed on production boards — read flash directly
PIN bypass	Physical: microprobing memory bus. Logical: extracting PIN from host software

2E — Social Engineering / Phishing

Attack Vector	Technique
Fake wallet app	Clones in app stores (iOS/Android) or GitHub repos with backdoored seed generation
Seed phrase phishing	Fake "wallet restore" sites, fake Ledger Live updates, "validate your wallet" scams
SIM swap	Bypass 2FA on exchange accounts to withdraw custodial funds
Fake hardware wallet	Clone devices with known keys or remote kill switch (see: Ledger supply chain 2023 counterfeit reports)

Phase 3: Testing Methodology Checklist

For each wallet under test:

•  Extract seed phrase from memory dump (unlocked state)

•  Extract seed from encrypted storage (brute-force weak passphrases)

•  Test RPC endpoint exposure (local + if accidentally exposed)

•  Check TLS cert validation on all API calls

•  Audit random number generation source

•  Verify HD derivation path conformity (BIP44)

•  Check for deterministic nonce reuse (ECDSA)

•  Review dependency tree for known CVEs

•  Test clipboard manipulation resistance

•  Verify firmware authenticity (hardware wallets)

•  Check physical debug interface exposure (hardware)

•  Attempt firmware downgrade (hardware)

•  Review logging: are addresses/keys written to disk/logs?

•  Check for wallet file encryption strength (weak KDF? pbkdf2 iterations?)

•  Test multi-sig setup verification (does UI show correct co-signers?)

•  Verify withdrawal address whitelist bypass (exchange wallets)

Phase 4: Tools

Category	Tools
Memory forensics	Volatility (plugins: bitcoin_wallet, ecdsa_keyfind), Rekall, LiME
Blockchain analysis	OXT (oxt.me), Chainalysis Reactor, Blockchair, BitIodine
Fuzzing	LibFuzzer + custom harness for tx parsing, AFL for wallet binaries
Static analysis	Slither (Solidity), Mythril, ConsenSys Diligence tools, semgrep rules for wallet code
Side-channel	ChipWhisperer (power/EM), HiFive (glitching), Proxmark3 (RFID)
Network	Nmap (RPC exposure), mitmproxy (intercept wallet traffic), Wireshark
Hardware	Bus Pirate, J-Link (JTAG/SWD), Saleae logic analyzer, hot air station (chip-off)

Phase 5: Risk Scoring

Finding	Severity	Example
Seed phrase in plaintext memory	Critical	bitcoind without encryption
Weak RNG	Critical	Predictable wallet generation
RPC exposed to network	High	rpcallowip=0.0.0.0
Nonce reuse	High	ETH tx with same v, r, s
PIN bypass via firmware downgrade	High	Ledger Nano firmware downgrade
Untrusted RPC provider	Medium	Default Infura logs all requests
Clipboard monitoring	Medium	Any wallet not using direct paste prevention
Deterministic wallet fingerprinting	Low	BIP44 gap limit analysis