CVE-2021-29441 Authentication bypass
Attackers can bypass authentication by spoofing the user-agent header, allowing unauthorized administrative access to the Nacos server.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-29441?
CVE-2021-29441 is a high-severity authentication bypass vulnerability in alibaba nacos, published on 27 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Nacos is a platform designed for dynamic service discovery and configuration and service management. In Nacos before version 1.4.1, when configured to use authentication (-Dnacos.core.auth.enabled=true) Nacos uses the AuthFilter servlet filter to enforce authentication. This filter has a backdoor that enables Nacos servers to bypass this filter and therefore skip authentication checks. This mechanism relies on the user-agent HTTP header so it can be easily spoofed. This issue may allow any user to carry out any administrative tasks on the Nacos server.
Weakness: CWE-290
Which versions are affected by CVE-2021-29441?
It affects 1 product.
Products include Alibaba Nacos.
How do I fix CVE-2021-29441?
Upgrade to a fixed version.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2021-29441 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-29441 exists.
Public exploit code: 1 Nuclei template and 4 proofs of concept on GitHub.