Vulnerability · Published Aug 9, 2023 · Assigned by mitre
CVE-2023-39910
High 7.5
In plain English
A high-severity security flaw in the affected software. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.8% (higher than 79% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
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.
Affected products (as reported)
References
- https://github.com/libbitcoin/libbitcoin-explorer/blob/20eba4db9a8a3476949d6fd08a589abda7fde3e3/src/commands/seed.cpp#L44
- https://github.com/libbitcoin/libbitcoin-explorer/blob/20eba4db9a8a3476949d6fd08a589abda7fde3e3/src/utility.cpp#L78
- https://github.com/libbitcoin/libbitcoin-system/blob/a1b777fc51d9c04e0c7a1dec5cc746b82a6afe64/src/crypto/pseudo_random.cpp#L66C12-L78
- https://milksad.info/disclosure.html
- https://news.ycombinator.com/item?id=37054862
- https://github.com/libbitcoin/libbitcoin-explorer/wiki/CVE-2023-39910