AUFS (Ubuntu 15.10) - 'allow_userns' Fuse/Xattr User Namespaces Privilege Escalation

Source: http://www.halfdog.net/Security/2016/AufsPrivilegeEscalationInUserNamespaces/ Introduction Problem description: Aufs is a union filesystem to mix content of different underlying filesystems, e.g. read-only medium with r/w RAM-fs. That is also allowed in user namespaces when module was...