dir-890l_firmware

An issue was discovered on D-Link DIR-890L with firmware 1.21B02beta01 and earlier, DIR-885L/R with firmware 1.21B03beta01 and earlier, and DIR-895L/R with firmware 1.21B04beta04 and earlier devices (all hardware revisions). Due to the predictability of the /docs/captcha_(number).jpeg URI, being local to the network, but unauthenticated to the administrator’s panel, an attacker can disclose the CAPTCHAs used by the access point and can elect to load the CAPTCHA of their choosing, leading to unauthorized login attempts to the access point.

The LAN-side Web-Configuration Interface has Stack-based Buffer Overflow vulnerability in the D-Link Wi-Fi router firmware DIR-890L DIR890LA1_FW107b09.bin and previous versions. The function created at 0x17958 of /htdocs/cgibin will call sprintf without checking the length of strings in parameters given by HTTP header and can be controlled by users easily. The attackers can exploit the vulnerability to carry out arbitrary code by means of sending a specially constructed payload to port 49152.