Since the announcement of the SolarWinds supply chain attack, intensive analysis has been done by Crowdstrike, FireEye (with additional details), Microsoft, Symantec, SolarWinds, and many others, to understand the attack’s workings both within SolarWinds and in the targeted networks. Here we focus on the code signing procedures, which seemingly failed at SolarWinds but likely could have mitigated the risk of the attack if they had been implemented and enforced to a higher standard.