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GHSA-4w5x-x539-ppf5
No affected components available
Problem Description
NATS nats-server through 2020-10-07 has Incorrect Access Control because of how expired credentials are handled.
The NATS accounts system has expiration timestamps on credentials; the https://github.com/nats-io/jwt library had an API which encouraged misuse and an IsRevoked() method which misused its own API.
A new IsClaimRevoked() method has correct handling and the nats-server has been updated to use this. The old IsRevoked() method now always returns true and other client code will have to be updated to avoid calling it.
The CVE identifier should cover any application using the old JWT API, where the nats-server is one of those applications.
Affected versions
JWT library
- all versions prior to 1.1.0
- fixed after nats-io/jwt PR 103 landed (2020-10-06)
NATS Server
- Version 2 prior to 2.1.9
- 2.0.0 through and including 2.1.8 are vulnerable.
- fixed with nats-io/nats-server PRs 1632, 1635, 1645
Impact
Time-based credential expiry did not work.
Workaround
Have credentials which only expire after fixes can be deployed.
Solution
Upgrade the JWT dependency in any application using it.
Upgrade the NATS server if using NATS Accounts.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.
Active exploitation in the wild has been confirmed. Immediate patching or mitigation is required.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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