Security Hardening Release
alphaV3.7 is a dedicated security hardening release that addresses 18 vulnerabilities identified during a comprehensive security audit. The release has also been validated in an isolated sandbox, with verification screenshots included below.
alphaV3.7 is a dedicated security hardening release that addresses 18 vulnerabilities identified during a comprehensive security audit. The fixes span the full severity spectrum from critical cryptographic weaknesses to low-severity defense-in-depth improvements. No new features are introduced; the sole focus is raising the security baseline of the SynapseNet node.
| Severity | Count |
|---|---|
| CRITICAL | 3 |
| HIGH | 4 |
| MEDIUM | 6 |
| LOW | 5 |
File: src/privacy/session_crypto.cpp
The custom stream cipher (SHA-256 in counter mode XOR'd with plaintext + HMAC-SHA256) has been completely replaced with OpenSSL AES-256-GCM. The insecure std::mt19937_64 PRNG used for nonce generation has been replaced with RAND_bytes() from OpenSSL. The new encrypt format is [12-byte IV][16-byte GCM tag][ciphertext], leveraging GCM's built-in authenticated encryption instead of a separate HMAC. Key material is now securely erased with OPENSSL_cleanse() on session destruction.
File: src/core/wallet.cpp
The legacy wallet loading path that used simple XOR encryption (plaintext[i] = ciphertext[i] ^ key[i % key.size()]) has been removed entirely. This cipher was trivially breakable with known-plaintext attacks. The legacyIteratedSha256Kdf function and LEGACY_KDF_EXISTS_FOR_MIGRATION_ONLY constant have been removed. Attempting to load a legacy-format wallet now returns an error directing users to the wallet migration tool.
File: src/core/consensus.cpp
Removed the all-zero signature bypass that allowed unsigned votes from "internal callers" to skip verification. The entire hasSignature check block has been replaced with a simple if (!vote.verify()) return false;. All votes must now carry a valid cryptographic signature regardless of origin.
File: src/web/rpc_server.cpp
Four distinct fixes applied:
- Error message sanitization: Replaced
e.what()in error responses with a generic "Internal server error" to prevent information leakage of internal exception details. - JSON response injection prevention: Added
escapeJsonString()helper that properly escapes",\, and control characters. Used when embeddingresponse.idin JSON output to prevent injection attacks. - Content-Length cap: Added a 4MB maximum on request body size. Requests exceeding this limit receive a 413 Payload Too Large response immediately.
- Session ID generation: Replaced nanosecond-timestamp-based session IDs with 16 random bytes from
RAND_bytes(), hex-encoded to 32 characters. This prevents session ID prediction attacks.
File: src/core/transfer.cpp
Added saturating arithmetic to Transaction::totalOutput(). When summing output amounts, if adding the next amount would overflow uint64_t, the function now returns UINT64_MAX instead of wrapping around. This prevents attackers from crafting transactions where outputs appear to sum to a small value due to integer overflow.
File: src/utils/serialize.cpp
Added a 4MB maximum length check in both readString() and readBytes() after reading the length varint but before allocating memory. Malformed messages with absurdly large length fields can no longer cause out-of-memory crashes or excessive allocation.
File: src/utils/serialize.cpp
Added a cap of 100,000 transactions per block in deserializeBlock(). This prevents a malicious peer from sending a block with billions of claimed transactions, which would cause excessive memory allocation via reserve().
Files: include/network/network.h, src/network/network.cpp
Added a uint64_t nonce field to the Message struct. On the receive side, each peer's PeerRxState now tracks a set of recently seen nonces (up to 10,000). Duplicate nonces from the same peer are rejected, preventing message replay attacks.
File: include/network/network.h
Added a remoteAddress field to HandshakeResult so that callers can verify the claimed node identity matches the actual socket peer address. This prevents a node from impersonating another node's identity during the handshake.
File: src/python/sandbox.cpp
Added __subclasses__, __mro__, __bases__, and __class__ to the forbidden patterns in checkBuiltins(). Added a restricted type() wrapper in wrapCode() that only allows single-argument calls (type inspection) and blocks 3-argument calls (dynamic class creation). This prevents Python sandbox escapes via class hierarchy traversal techniques like ().__class__.__bases__[0].__subclasses__().
Files: src/core/wallet.cpp, src/crypto/keys.cpp
Increased PBKDF2-HMAC iteration count for mnemonic-to-seed derivation from 2,048 to 100,000 in both the wallet's deriveMasterSeed() and the Keys::fromMnemonic() function. This makes brute-force attacks against mnemonic passphrases approximately 50x more expensive.
Files: src/core/wallet.cpp, src/crypto/crypto.cpp, src/privacy/session_crypto.cpp
Replaced all std::memset and volatile pointer zeroing loops for key material with OPENSSL_cleanse(). The previous volatile-pointer approach, while better than plain memset, is not guaranteed to survive compiler optimizations in all cases. OPENSSL_cleanse() is specifically designed to resist dead-store elimination and is the industry standard for secure memory wiping.
File: src/network/network.cpp
Extended the SOCKS5 proxy connection to support both no-auth (0x00) and username/password (0x02) authentication methods per RFC 1929. Added socksUsername and socksPassword fields to NetworkConfig. When configured, the node performs the authentication subnegotiation after the initial greeting. Backward compatible: if no credentials are configured, no-auth is used.
File: src/network/network.cpp
Added resolveHostWithTimeout() wrapper that runs getaddrinfo() in a separate thread with a 3-second timeout. Since getaddrinfo() is inherently blocking and has no built-in timeout, a malicious or slow DNS server could previously stall the node indefinitely. The timeout prevents this denial-of-service vector.
File: src/web/rpc_server.cpp
Added per-authentication-token rate limiting alongside the existing per-IP limiting. A std::map<std::string, RateLimitEntry> authTokenRateLimits tracks request counts per auth token within the rate limit window. This prevents a single authenticated user from monopolizing the RPC server even if they connect from multiple IP addresses.
File: src/core/update_installer.cpp
Added checks for URL-encoded path traversal sequences (%2e, %2E, %00) and null byte injection (\0) in update manifest target paths. The existing .. check only caught literal dot-dot sequences; an attacker could bypass it with URL-encoded equivalents.
File: src/model/model_download.cpp
Verified that verifyChecksum() properly computes SHA-256 of downloaded files and compares against the expected hash. The function is called after download completes and before the temp file is renamed to its final path. Failed verification results in file deletion and an error callback.
File: src/core/consensus.cpp
Mixed additional entropy into the validator selection seed. Instead of using only the eventId, the selection now incorporates the total weight of the validator set and the public keys of the first validators in the sorted eligible list. This data is double-hashed through SHA-256 to produce the final pick hash, making the selection unpredictable even if the validator set composition is known.
| File | Fixes |
|---|---|
src/privacy/session_crypto.cpp |
1, 12 |
src/core/wallet.cpp |
2, 11, 12 |
src/core/consensus.cpp |
3, 18 |
src/web/rpc_server.cpp |
4, 15 |
src/core/transfer.cpp |
5 |
src/utils/serialize.cpp |
6, 7 |
include/network/network.h |
8, 9, 13 |
src/network/network.cpp |
8, 13, 14 |
src/network/handshake.cpp |
9 |
src/python/sandbox.cpp |
10 |
src/crypto/keys.cpp |
11 |
src/crypto/crypto.cpp |
12 |
src/core/update_installer.cpp |
16 |
src/model/model_download.cpp |
17 |
The following verification screenshots were generated from isolated sandbox test runs and source-level validation notes for alphaV3.7.
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