CVE-2020-15237 Timing attack in Shrine
Attackers can guess derivation URL signatures via timing attacks in Shrine's derivation_endpoint plugin, potentially bypassing access controls.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-15237?
CVE-2020-15237 is a medium-severity vulnerability in shrinerb shrine, published on 5 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In Shrine before version 3.3.0, when using the `derivation_endpoint` plugin, it's possible for the attacker to use a timing attack to guess the signature of the derivation URL. The problem has been fixed by comparing sent and calculated signature in constant time, using `Rack::Utils.secure_compare`. Users using the `derivation_endpoint` plugin are urged to upgrade to Shrine 3.3.0 or greater. A possible workaround is provided in the linked advisory.
Which versions are affected by CVE-2020-15237?
2 open source packages ship an affected version, including shrine. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
shrine RubyGems | All versions | 3.3.0 |
shrine RubyGems | All versions | 3.3.0 |
Products include Shrinerb Shrine.
How do I fix CVE-2020-15237?
Upgrade shrine to 3.3.0 or later.
Is CVE-2020-15237 being exploited?
There is no known exploitation of CVE-2020-15237 in the wild and no public exploit code.
Sources
Also known as GHSA-5jjv-x4fq-qjwp.