The Schneider Electric Quantum Ethernet Module, as used in the Quantum 140NOE771* and 140CPU65* modules, the Premium TSXETY* and TSXP57* modules, the M340 BMXNOE01* and BMXP3420* modules, and the STB DIO STBNIC2212 and STBNIP2* modules, uses hardcoded passwords for the (1) AUTCSE, (2) AUT_CSE, (3) fdrusers, (4) ftpuser, (5) loader, (6) nic2212, (7) nimrohs2212, (8) nip2212, (9) noe77111_v500, (10) ntpupdate, (11) pcfactory, (12) sysdiag, (13) target, (14) test, (15) USER, and (16) webserver accounts, which makes it easier for remote attackers to obtain access via the (a) TELNET, (b) Windriver Debug, or (c) FTP port.

The ComputePassword function in the Schneider Electric Quantum Ethernet Module on the NOE 771 device (aka the Quantum 140NOE771* module) generates the password for the fwupgrade account by performing a calculation on the MAC address, which makes it easier for remote attackers to obtain access via a (1) ARP request message or (2) Neighbor Solicitation message.

The modbus_125_handler function in the Schneider Electric Quantum Ethernet Module on the NOE 771 device (aka the Quantum 140NOE771* module) allows remote attackers to install arbitrary firmware updates via a MODBUS 125 function code to TCP port 502.