Removal of filesystem attribute protections from the user’s .ssh directory followed by deletion and recreation of the directory and insertion of a new public key into authorized_keys. This pattern reflects deliberate modification of SSH trust configuration to establish persistent key-based access.

Automated SIP OPTIONS requests used to validate reachable VoIP endpoints and enumerate service capabilities without initiating a call session. The client sends standalone OPTIONS probes with high-entropy or unusually long Call-ID values, a pattern commonly associated with scripted scanning frameworks or VoIP reconnaissance tooling. Such activity is typically observed during infrastructure discovery phases where attackers identify responsive SIP servers, supported methods, and potential targets for toll fraud, brute-force registration attempts, or later exploitation campaigns.