An exploitable stack buffer overflow vulnerability vulnerability exists in the iocheckd service ‘I/O-Check’ functionality of WAGO PFC 200 Firmware version 03.02.02(14). An attacker can send a specially crafted packet to trigger the parsing of this cache file.The destination buffer sp+0x40 is overflowed with the call to sprintf() for any gateway values that are greater than 512-len(‘/etc/config-tools/config_default_gateway number=0 state=enabled value=‘) in length. A gateway value of length 0x7e2 will cause the service to crash.

An exploitable stack buffer overflow vulnerability vulnerability exists in the iocheckd service ‘I/O-Check’ functionality of WAGO PFC 200 Firmware version 03.02.02(14). An attacker can send a specially crafted packet to trigger the parsing of this cache file.The destination buffer sp+0x40 is overflowed with the call to sprintf() for any gateway values that are greater than 512-len(‘/etc/config-tools/config_default_gateway number=0 state=enabled value=‘) in length. A gateway value of length 0x7e2 will cause the service to crash.

An attacker needs an authorized login on the device in order to exploit the herein mentioned vulnerabilities.

The reported vulnerabilities allow a local attacker with valid login credentials who is able to create files on the device to change the devices settings, e.g. default gateway address, time server etc. and potentially execute code.