An issue was discovered in Atos Eviden SMC xScale before 1.6.6. During initialization of nodes, some configuration parameters are retrieved from management nodes. These parameters embed credentials whose integrity and confidentiality may be important to the security of the HPC configuration. Because these parameters are needed for initialization, there is no available mechanism to ensure access control on the management node, and a mitigation measure is normally put in place to prevent access to unprivileged users. It was discovered that this mitigation measure does not survive a reboot of diskful nodes. (Diskless nodes are not at risk.) The mistake lies in the cloudinit configuration: the iptables configuration should have been in the bootcmd instead of the runcmd section.