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CVE-2021-27342 describes a vulnerability in the telnetd service of D-Link DIR-842 routers (firmware 3.0.2), where the authentication brute-force protection mechanism can be bypassed. The anti-brute-force cool-down delay, intended to slow down repeated login attempts, can be circumvented by a remote attacker using a timing-based side-channel attack. This allows the attacker to continue brute-forcing credentials without being subject to the intended delay.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This repository contains a Python exploit script (dlink-telnet-exploit-CVE-2021-27342.py) targeting D-Link routers vulnerable to CVE-2021-27342. The exploit leverages a timing side-channel to bypass the telnet authentication brute-force protection, reducing the enforced delay between failed login attempts from 3 seconds to less than 0.1 seconds. This allows for rapid brute-forcing of the admin password via the telnet service. The script can use a user-supplied wordlist or a built-in demo list of common passwords. The main attack vector is network-based, targeting the telnet service (default IP 192.168.0.1, port 23) of the router. The repository includes a README, a license file, and the exploit script. The exploit is operational and provides valid credentials if successful.
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