OISF suricata-update unsafely deserializes YAML data

OISF suricata-update version 1.0.0a1 contains an Insecure Deserialization vulnerability in the insecure yaml.load-Function as used in the following files: config.py:136, config.py:142, sources.py:99 and sources.py:131. The "list-sources"-command is affected by this bug. that can result in Remote Code Execution(even as root if suricata-update is called by root). This attack appears to be exploitable via a specially crafted yaml-file at https://www.openinfosecfoundation.org/rules/index.yaml. This vulnerability appears to have been fixed in 1.0.0b1.