Elaborating on the bug, Grzegorz Wypych, from IBM X-Force Red team, said that the firmware bug affected both home and business routers. To exploit the bug, an attacker merely had to send an HTTP request including a character string longer than the allowed number. As a result, the user password would become void. As stated in their blog post,
At first, we tried to send a shorter string, with only a few bytes. This short string went through and corrupted the password file. The result is that the user would not be able to log in, and nor would the attacker… Next, we tried sending through a password longer than the allowed number of characters. This time, the password was voided altogether, and the value was now empty.Consequently, the researchers could gain access to FTP and TELNET with only the username ‘admin’ without any password. This way, an attacker could not only take over the router but would also lock out the legitimate user from using the device.
TP-Link has issued patches for the firmware. Users of vulnerable routers must ensure installing the latest updates to ensure they are protected.
Recently, researchers also discovered a critical command execution bug in D-Link routers, which the vendors refused to patch.
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