Standard antivirus tools (Malwarebytes, Defender) look for .exe files. The 015-CTR threat often lives in Windows Group Policies and Registry Run keys . The 015-ctrremove Tool is coded to specifically look for these registry anomalies.
If you are unable to download the 015-ctrremove Tool due to network restrictions (the virus blocks security sites), use this manual PowerShell command as a temporary fix: Download 015-ctrremove Tool