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CVE-2021-20134

HIGHCVSS 8.4/10EPSS 7.53%

Last modified

CVE-2021-20134 is a high-severity vulnerability rated 8.4/10 on the CVSS scale. Quagga Services on D-Link DIR-2640 less than or equal to version 1.11B02 are affected by an absolute path traversal vulnerability that allows a remote, authenticated attacker to set an arbitrary file on the router's filesystem as the log file used by either Quagga service (zebra or ripd). Subsequent log messages will be appended to the file, prefixed by a timestamp and some logging metadata. EPSS estimates a 7.53% chance of exploitation in the next 30 days.

Description

Quagga Services on D-Link DIR-2640 less than or equal to version 1.11B02 are affected by an absolute path traversal vulnerability that allows a remote, authenticated attacker to set an arbitrary file on the router's filesystem as the log file used by either Quagga service (zebra or ripd). Subsequent log messages will be appended to the file, prefixed by a timestamp and some logging metadata. Remote code execution can be achieved by using this vulnerability to append to a shell script on the router's filesystem, and then awaiting or triggering the execution of that script. A remote, unauthenticated root shell can easily be obtained on the device in this fashion.

Metrics

CVSS 3.1
8.4/10

CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

EPSS Probability
7.53%

93.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
DlinkDir-2640-Us Firmware<= 1.11b02

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-20134?
Quagga Services on D-Link DIR-2640 less than or equal to version 1.11B02 are affected by an absolute path traversal vulnerability that allows a remote, authenticated attacker to set an arbitrary file on the router's filesystem as the log file used by either Quagga service (zebra or ripd). Subsequent log messages will be appended to the file, prefixed by a timestamp and some logging metadata. Remote code execution can be achieved by using this vulnerability to append to a shell script on the router's filesystem, and then awaiting or triggering the execution of that script. A remote, unauthenticated root shell can easily be obtained on the device in this fashion.
How severe is CVE-2021-20134?
CVE-2021-20134 has a CVSS score of 8.4/10 (HIGH severity). The EPSS model estimates a 7.53% probability of exploitation in the next 30 days.
How do I fix CVE-2021-20134?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-20134?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST