Horizon Alert
Summary of the vulnerability and why it matters
This vulnerability in Zcash node software could lead to a consensus split, where different versions of the software disagree on the validity of transactions. This means some nodes might accept and process transactions that others reject, potentially disrupting the Zcash network.
- Disrupts network integrity.
- Affects all Zcash nodes.
- Network consensus is broken.
Attack Path
How an attacker could exploit the issue
An attacker could exploit this flaw to cause a consensus split within the Zcash network. By submitting specially crafted transactions that violate specific sighash type rules, a malicious actor could trick vulnerable Zebra nodes into accepting and mining invalid blocks. This would effectively bifurcate the blockchain, making it appear as though two separate versions of the ledger exist.
- No authentication required.
- Targets Zebra node network communication.
- Feasibility depends on node version.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability could allow an attacker to cause a consensus split by submitting invalid blocks, potentially disrupting the Zcash network. While direct financial gain is not immediately obvious, network disruption and potential for exploitation during a split could be attractive. The consensus-critical nature of the issue makes it a target for actors interested in destabilizing or manipulating the Zcash ecosystem.
- Affects Zcash node software.
- Potential for network disruption.
- No public exploit reported.
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
Prioritize updating Zcash node software to prevent consensus splits and ensure network integrity. This critical vulnerability allows for the acceptance and mining of invalid blocks, directly impacting network stability.
- Update zebrad to 4.3.1 or later.
- Update zebra-script to 5.0.2 or later.
- Monitor network for consensus deviations.
