Adversaries may abuse CMSTP to proxy execution of malicious code. The Microsoft Connection Manager Profile Installer (CMSTP.exe) is a command-line program used to install Connection Manager service profiles. [1] CMSTP.exe accepts an installation information file (INF) as a parameter and installs a service profile leveraged for remote access connections.
Adversaries may supply CMSTP.exe with INF files infected with malicious commands. [2] Similar to Regsvr32 / "Squiblydoo", CMSTP.exe may be abused to load and execute DLLs [3] and/or COM scriptlets (SCT) from remote servers. [4] [5] [6] This execution may also bypass AppLocker and other application control defenses since CMSTP.exe is a legitimate, signed Microsoft application.
CMSTP.exe can also be abused to Bypass User Account Control and execute arbitrary commands from a malicious INF through an auto-elevated COM interface. [3] [5] [6]
| ID | Name | Description |
|---|---|---|
| G0080 | Cobalt Group |
Cobalt Group has used the command |
| G0069 | MuddyWater |
MuddyWater has used CMSTP.exe and a malicious INF to execute its POWERSTATS payload.[10] |
| ID | Mitigation | Description |
|---|---|---|
| M1042 | Disable or Remove Feature or Program |
CMSTP.exe may not be necessary within a given environment (unless using it for VPN connection installation). |
| M1038 | Execution Prevention |
Consider using application control configured to block execution of CMSTP.exe if it is not required for a given system or network to prevent potential misuse by adversaries. |
| ID | Data Source | Data Component |
|---|---|---|
| DS0017 | Command | Command Execution |
| DS0029 | Network Traffic | Network Connection Creation |
| DS0009 | Process | Process Creation |
Use process monitoring to detect and analyze the execution and arguments of CMSTP.exe. Compare recent invocations of CMSTP.exe with prior history of known good arguments and loaded files to determine anomalous and potentially adversarial activity.
Sysmon events can also be used to identify potential abuses of CMSTP.exe. Detection strategy may depend on the specific adversary procedure, but potential rules include: [6]