Known as "Token Kidnapping".
Advisory: SB2008041402 - Multiple vulnerabilities in Microsoft Windows
Vulnerable component: Windows
CVSSv3 score: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls
The vulnerability allows a local attacker to gain elevated privileges on the target system.
The weakness exists due to improper isolation of processes in the RPCSS service. Accessing the computer under the context of a NetworkService or LocalService account an attacker can obtain privileged security tokens and execute code with privileges of SYSTEM account.
Successful exploitation of the vulnerability results in privilege escalation allowing to execute arbitrary code and take complete control of an affected system.
Note: this vulnerability was being actively exploited.