The assailant can and so consumption the embed webserver to effort the workable CLI access code to carry through instruction as tooth root and exfiltrate entropy . 72408A , 9008A , 9016A , 92408A , 92416A , 9288 , 97024P , 97028P , 97042P , 97084P , 97168P , FD1002S , FD1104S , FD1104SN , FD1204S - R2 , FD1204SN , FD1204SN - R2 , FD1208S - R2 , FD1216S - R1 , FD1608GS , FD1608SN , FD161616SN , and FD8000 . The vulnerability were discover in December 2019 , and this hebdomad the research worker in agreement to publicly expose their consequence , lay claim some of the back entrance were “ deliberately invest by the seller ” The encryption algorithm use to depot countersign USA XOR with a hardcoded value , and outback ascendency of SSL / TLS joining is not stick out . The researcher distinguish extra impacted poser through inactive analytic thinking , viz. The ship’s company ’s OLTs are available for purchase under several denounce , include BLIY , OptiLink , V - SOL CN , and C - Data , offer access to numerous customer ( in some guinea pig up to 1024 ) , with some of the device moved too patronage multiple 10 - Gb uplink . backdoor credentials have been feel to alter between microcode translation ( discover twosome let in suma123 / panger123 , guest/[empty ] , etymon / root126 , debug / debug124 ) and trafficker but do furnish admittance to the involve gimmick . The investigator too detect that an intruder with backdoor approach to the OLT can slip executive credential through the statement - personal credit line port ( CLI ) . In add-on , they ascertain that vane and telnet certificate and SNMP community of interests could be draw out without assay-mark , and credential lay in in bare school text . The researcher bring out during their investigating that a telnet server melt on the twist and accessible from the WAN user interface can be abuse to re-start the arrangement remotely , without assay-mark . security measure researcher Pierre Kim and Alexandre Torres name that many exposure move the FD1104B and FD1108SN OLTs , include a telnet server that can be get at from both the WAN and FTTH LAN port .