CVE-2021-3761 OctoRPKI lacks contextual out-of-bounds check when validating RPKI ROA maxLength values
Attackers can crash RTR sessions by sending invalid RPKI data, disabling origin validation and enabling BGP hijacks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-3761?
CVE-2021-3761 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 9 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Any CA issuer in the RPKI can trick OctoRPKI prior to 1.3.0 into emitting an invalid VRP "MaxLength" value, causing RTR sessions to terminate. An attacker can use this to disable RPKI Origin Validation in a victim network (for example AS 13335 - Cloudflare) prior to launching a BGP hijack which during normal operations would be rejected as "RPKI invalid". Additionally, in certain deployments RTR session flapping in and of itself also could cause BGP routing churn, causing availability issues.
Weakness: CWE-787
Which versions are affected by CVE-2021-3761?
3 open source packages ship an affected version, including github.com/cloudflare/cfrpki. It affects 2 products.
| Package | Affected | Fixed in |
|---|---|---|
github.com/cloudflare/cfrpki Go | All versions | 1.3.0 |
github.com/cloudflare/cfrpki Go | All versions | 1.3.0 |
github.com/cloudflare/cfrpki Go | All versions | 1.3.0 |
Products include Cloudflare Octorpki, Debian Debian Linux.
How do I fix CVE-2021-3761?
Upgrade github.com/cloudflare/cfrpki to 1.3.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-3761 being exploited?
There is no known exploitation of CVE-2021-3761 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
- CVE-2021-3978 Improper Preservation of Permissions in github.com/cloudflare/cfrpki/cmd/octorpki
- CVE-2021-3907 Arbitrary filepath traversal via URI injection
- CVE-2021-3908 Infinite certificate chain depth results in OctoRPKI running forever
- CVE-2022-3616 OctoRPKI crash when maximum iterations number is reached
- CVE-2021-3909 Infinite open connection causes OctoRPKI to hang forever
Sources
Also known as DEBIAN-CVE-2021-3761, GHSA-c8xp-8mf3-62h9, GO-2022-0246.