CVE-2021-21234

published 2021-01-05

CVE-2021-21234: spring-boot-actuator-logview in a library that adds a simple logfile viewer as spring boot actuator endpoint. It is maven package…

Priority P1 78 high 7.7 CVSS 3.1

AV N AC L PR L UI N S C C H I N A N

ITW EXPLOIT VulnCheck KEV

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.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
lukashinsch	spring-boot-actuator-logview	< 0.2.13	0.2.13
spring-boot-actuator-logview_project	spring-boot-actuator-logview	<= 0.2.12	—

Detection & IOCs extracted from sources · hover to see the quote

url /manage/log/view?filename=/windows/win.ini&base=../../../../../../../../../../↗

url /log/view?filename=/windows/win.ini&base=../../../../../../../../../../↗

url /manage/log/view?filename=/etc/passwd&base=../../../../../../../../../../↗

url /log/view?filename=/etc/passwd&base=../../../../../../../../../../↗

path /manage/log/view↗

sigma

HTTP GET requests to /manage/log/view or /log/view with 'base' parameter containing '../' sequences and status_code 200 with text/plain content-type

• → Exploit requests target the 'base' parameter (not 'filename') with directory traversal sequences (e.g., '../../../../../../../../../../') on the Spring Boot Actuator logview endpoints /manage/log/view or /log/view. ↗
• → Successful exploitation returns HTTP 200 with Content-Type 'text/plain' and file contents such as /etc/passwd (matching regex 'root:.*:0:0:') or Windows win.ini (containing 'bit app support', 'fonts', 'extensions').
• → Monitor HTTP GET requests to actuator logview endpoints where the 'base' query parameter contains sequences of '../' (path traversal), especially combined with absolute filenames like '/etc/passwd' or '/windows/win.ini'. ↗
• → The vulnerable maven package is 'eu.hinsch:spring-boot-actuator-logview' versions before 0.2.13. Identify deployments exposing /log/view or /manage/log/view actuator endpoints. ↗

• · The logview endpoint may be mounted under a custom actuator base path (e.g., /manage/log/view vs /log/view). Both paths should be monitored as the Nuclei template probes both variants.
• · Access to the logview endpoint can be restricted by deploying behind a reverse proxy, which may suppress or alter the HTTP response indicators used for detection. ↗
• · The 'filename' parameter alone is insufficient for exploitation (it was patched earlier); the attack vector specifically requires the 'base' parameter to carry the traversal payload. ↗

CVSS provenance

nvd v3.1 7.7 HIGH CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

nvd v2.0 4.0 MEDIUM AV:N/AC:L/Au:S/C:P/I:N/A:N

vulncheck 7.7 HIGH

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CWE-22