CVE-2019-16764 PowAssent is susceptible to denial of service attacks
Attackers can crash the application by exhausting the atom table via user-controlled input in PowAssent, requiring a library update.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2019-16764?
CVE-2019-16764 is a medium-severity denial of service vulnerability in pow-auth pow_assent, published on 25 Nov 2019. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
The use of `String.to_atom/1` in PowAssent is susceptible to denial of service attacks. In `PowAssent.Phoenix.AuthorizationController` a value is fetched from the user provided params, and `String.to_atom/1` is used to convert the binary value to an atom so it can be used to fetch the provider configuration value. This is unsafe as it is user provided data, and can be used to fill up the whole atom table of ~1M which will cause the app to crash.
Weakness: CWE-400
Which versions are affected by CVE-2019-16764?
2 open source packages ship an affected version, including pow_assent. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
pow_assent Hex | All versions | 0.4.4 |
pow_assent Hex | All versions | 0.4.4 |
Products include Powauth Powassent.
How do I fix CVE-2019-16764?
Upgrade pow_assent to 0.4.4 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-2019-16764 being exploited?
There is no known exploitation of CVE-2019-16764 in the wild and no public exploit code.
Sources
Also known as GHSA-368c-xvrv-x986, GHSA-5653-437f-5hmc.