CVE-2021-21234 Directory Traversal
An attacker can read arbitrary files outside the logging directory by manipulating the base folder parameter in the log viewer endpoint.
- 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-2021-21234?
CVE-2021-21234 is a high-severity path traversal vulnerability in lukashinsch spring-boot-actuator-logview, published on 5 Jan 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
spring-boot-actuator-logview in a library that adds a simple logfile viewer as spring boot actuator endpoint. It is maven package "eu.hinsch:spring-boot-actuator-logview". In spring-boot-actuator-logview before version 0.2.13 there is a directory traversal vulnerability. The nature of this library is to expose a log file directory via admin (spring boot actuator) HTTP endpoints. Both the filename to view and a base folder (relative to the logging folder root) can be specified via request parameters. While the filename parameter was checked to prevent directory traversal exploits (so that `filename=../somefile` would not work), the base folder parameter was not sufficiently checked, so that `filename=somefile&base=../` could access a file outside the logging base directory). The vulnerability has been patched in release 0.2.13. Any users of 0.2.12 should be able to update without any issues as there are no other changes in that release. There is no workaround to fix the vulnerability other than updating or removing the dependency. However, removing read access of the user the application is run with to any directory not required for running the application can limit the impact. Additionally, access to the logview endpoint can be limited by deploying the application behind a reverse proxy.
Weakness: CWE-22
Which versions are affected by CVE-2021-21234?
2 open source packages ship an affected version, including eu.hinsch:spring-boot-actuator-logview. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
eu.hinsch:spring-boot-actuator-logview Maven | All versions | 0.2.13 |
eu.hinsch:spring-boot-actuator-logview Maven | All versions | 0.2.13 |
Products include Spring-Boot-Actuator-Logview Project Spring-Boot-Actuator-Logview.
How do I fix CVE-2021-21234?
Upgrade eu.hinsch:spring-boot-actuator-logview to 0.2.13 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2021-21234 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-21234 exists.
Public exploit code: 1 Nuclei template and 2 proofs of concept on GitHub.
Other vulnerabilities in lukashinsch spring-boot-actuator-logview
Sources
Also known as GHSA-p4q6-qxjx-8jgp.