CVE-2021-20153: trendnet tew-827dru_firmware Link Following

Vulnerability summary

CVE-2021-20153 is a medium (CVSS 6.9) Link Following vulnerability in trendnet tew-827dru_firmware. EPSS estimates a 0.96% chance of exploitation in the next 30 days, higher than 61% of scored vulnerabilities.

Timeline

1. 30-12-2021
   PublishedVulnerability first disclosed.
2. 03-08-2024
   Last modifiedVulnerability information updated.

Description

Trendnet AC2600 TEW-827DRU version 2.08B01 contains a symlink vulnerability in the bittorrent functionality. If enabled, the bittorrent functionality is vulnerable to a symlink attack that could lead to remote code execution on the device. If an end user inserts a flash drive with a malicious symlink on it that the bittorrent client can write downloads to, then a user is able to download arbitrary files to any desired location on the devices filesystem, which could lead to remote code execution. Example directories vulnerable to this include "config", "downloads", and "torrents", though it should be noted that "downloads" is the only vector that allows for arbitrary files to be downloaded to arbitrary locations.

• CWE-59Improper Link Resolution Before File Access ('Link Following')The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.