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high·Product Based Web Vulnerabilities·Updated Dec 16, 2023

CVE-2021-21234 Scanner

Detects 'Directory Traversal' vulnerability in Spring Boot Actuator Logview affects v. before 0.2.13.

Est. Time~10 seconds
Scan TypeSingle Scan
Targetsurl
CostFree
2.1k
Times Used
continuous scan runs
4.8k
Continuously Checked
assets under CS
0
Vulnerabilities Found
confirmed findings
References
CVECVE-2021-21234
7.7
CVSShigh
Exploitable remotely over the internet · low-privilege account sufficient.

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.

Attack Vector
Network
Privileges Req.
Low
User Interaction
None
Affected
spring-boot-actuator-logviewby lukashinsch
< 0.2.13
Updated Aug 21, 2026View on NVD →
Detail

Spring Boot Actuator Logview is a library designed to provide a simple logfile viewer via Spring Boot's actuator endpoint. The package, eu.hinsch:spring-boot-actuator-logview, is typically used by developers to expose log file directories as admin HTTP endpoints. Users can specify the filename and base folder (relative to the logging folder root) through request parameters to access their logs. The library is widely utilized because of its ease of use and fast implementation.

Unfortunately, the library contained a significant vulnerability, also known as CVE-2021-21234, before version 0.2.13. The flaw involves directory traversal exploitation where hackers could access resources outside of the intended directory, compromising the system's security. While the filename parameter was checked to prevent attacks, the base folder parameter was not sufficiently validated, allowing attackers to exploit it.

When this vulnerability is exploited, it can lead to severe consequences for the victim. Attackers could, for instance, access files outside the intended directory, which may include sensitive information such as user credentials. This information can then be used for phishing scams or even lead to identity theft, causing severe financial and reputational damage.

s4e.io is a platform that provides pro features to enable businesses to identify vulnerabilities in their digital assets. Thanks to these features, teams can easily and quickly learn about vulnerabilities that could compromise the security of their systems. It is crucial for developers to stay informed and take advantage of these types of tools to stay ahead of potential threats that could impact their business operations.

 

REFERENCES

Solution Advice

To protect against this vulnerability, developers can take multiple precautions to limit the impact of the attack. Possible precautions include, but are not limited to:

  • Updating to version 0.2.13 or newer versions to fix the vulnerability
  • Limiting access to logview endpoints only to required personnel
  • Limiting access to necessary folders by removing read access for non-essential users
  • Deploying the application behind a reverse proxy

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CVE-2021-21234 scanner - Directory Traversal vulnerability in Spring Boot Actuator Logview | S4E