A cybersecurity analyst is reviewing the logs of a Citrix NetScaler Gateway running on a FreeBSD 8.4 server and saw the following output: -=-=-=-=--=-=-=-=--=-=-=-=--=-=-=-=--=-=-=-=--=-=-=-=--=-=-=-=- 10.1.1.1 - - [10/Jan/2020:13:23:51 +0000] "POST /vpn/../vpns/portal/scripts/newbm.pl HTTP/1.1" 200 143 "https://10.1.1.2/" "USERAGENT " 10.1.1.1 - - [10/Jan/2020:13:23:53 +0000] "GET /vpn/../vpns/portal/backdoor.xml HTTP/1.1" 200 941 "-" "USERAGENT" 10.1.1.1 - - [10/Jan/2020:16:12:31 +0000] "POST /vpns/portal/scripts/newbm.pl HTTP/1.1" 200 143 "https://10.1.1.2/" "USERAGENT" -=-=-=-=--=-=-=-=--=-=-=-=--=-=-=-=--=-=-=-=--=-=-=-=--=-=-=-=- What type of attack was most likely being attempted by the attacker?