Cloud security company Wiz has published information on an Oracle Cloud Infrastructure (OCI) vulnerability allowing attackers to modify users’ storage volumes without authorization.
Referred to as #AttachMe and mentioned in Oracle’s July 2022 Critical Patch Update, the vulnerability could have exposed sensitive data to attackers knowing the victim’s Oracle Cloud Identifier (OCID).
“OCI customers could have been targeted by an attacker with knowledge of #AttachMe. Any unattached storage volume, or attached storage volumes allowing multi-attachment, could have been read from or written to as long as an attacker had its Oracle Cloud Identifier (OCID),” Wiz security researcher Elad Gabay explains.
Essentially, because of this vulnerability, cloud isolation in OCI no longer worked, allowing anyone to attach disks to virtual machines in other accounts, without requiring permissions.
An attacker could exploit the security issue by acquiring the OCID of the victim and then initiating a compute instance on a tenant located on the same availability domain as the target volume.
After attaching a volume, the attacker could then target the victim’s volume to gain read/write privileges to it. The target volume needs to be either detached or attached as shareable, the security researcher explains.
In addition to being able to exfiltrate sensitive data or steal credentials for lateral movement, this type of access could allow an attacker to modify block volumes and boot volumes to gain code execution capabilities.
The bug, Gabay explains, resided in the validation of write permissions when attaching a volume, allowing for this attach operation to be performed without any authorization.
“In addition, attachment was possible across different tenancies: we managed to attach a volume from one tenancy to a compute instance in another tenancy,” the researcher notes.
Successful exploitation of this bug could have allowed an attacker to query all available volumes, obtain their OCIDs, and then access the information stored on them.
Because OCIDs are not generally considered secrets, meaning that they can be found via online searches, Wiz considers that #AttachMe could have been easily exploited for privilege escalation within the same compartment or tenancy, as well as for cross-tenant access.
Oracle addressed the vulnerability one day after Wiz reported it in June. The tech giant mentioned Gabay’s contribution in its July 2022 Critical Patch Update advisory.