Vulnerabilities > CVE-2023-39910 - Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) vulnerability in Libbitcoin Explorer
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
HIGH Integrity impact
NONE Availability impact
NONE Summary
The cryptocurrency wallet entropy seeding mechanism used in Libbitcoin Explorer 3.0.0 through 3.6.0 is weak, aka the Milk Sad issue. The use of an mt19937 Mersenne Twister PRNG restricts the internal entropy to 32 bits regardless of settings. This allows remote attackers to recover any wallet private keys generated from "bx seed" entropy output and steal funds. (Affected users need to move funds to a secure new cryptocurrency wallet.) NOTE: the vendor's position is that there was sufficient documentation advising against "bx seed" but others disagree. NOTE: this was exploited in the wild in June and July 2023.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| Application | 7 |
Common Weakness Enumeration (CWE)
References
- https://milksad.info/disclosure.html
- https://github.com/libbitcoin/libbitcoin-explorer/blob/20eba4db9a8a3476949d6fd08a589abda7fde3e3/src/utility.cpp#L78
- https://news.ycombinator.com/item?id=37054862
- https://github.com/libbitcoin/libbitcoin-explorer/blob/20eba4db9a8a3476949d6fd08a589abda7fde3e3/src/commands/seed.cpp#L44
- https://github.com/libbitcoin/libbitcoin-system/blob/a1b777fc51d9c04e0c7a1dec5cc746b82a6afe64/src/crypto/pseudo_random.cpp#L66C12-L78
- https://github.com/libbitcoin/libbitcoin-explorer/wiki/CVE-2023-39910