The hypothesis is that the detected activity may indicate an adversary attempting to exfiltrate data or establish a foothold through a suspicious HTTP request associated with the Cylance OP Cleaver tool. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify potential early-stage compromise or data exfiltration attempts that may not be detected by traditional methods.
YARA Rule
rule pvz_out
{
meta:
author = "Cylance"
date = "2014-12-02"
description = "http://cylance.com/opcleaver"
strings:
$s1 = "Network Connectivity Module" wide
$s2 = "OSPPSVC" wide
condition:
all of them
}
This YARA rule can be deployed in the following contexts:
This rule contains 2 string patterns in its detection logic.
Scenario: A system administrator is using PowerShell to perform a scheduled maintenance task that involves downloading a script from a trusted internal repository.
Filter/Exclusion: Exclude events where the source IP is from the internal network and the command line contains powershell.exe with a known maintenance script path.
Scenario: A Windows Task Scheduler job is configured to run a legitimate batch file that connects to an external API for data synchronization.
Filter/Exclusion: Exclude events where the process name is schtasks.exe and the command line includes a known internal API endpoint.
Scenario: A Docker container is being built using a CI/CD pipeline, which involves pulling an image from a public registry like Docker Hub.
Filter/Exclusion: Exclude events where the process is related to Docker (e.g., docker.exe) and the image name is from a known trusted registry.
Scenario: A Microsoft SQL Server Agent job is executing a stored procedure that connects to an external service for reporting purposes.
Filter/Exclusion: Exclude events where the process is sqlagent.exe and the connection string matches a known internal reporting service.
Scenario: A Windows Update task is running in the background, which temporarily connects to Microsoft servers to download patches.
Filter/Exclusion: Exclude events where the process is wuauserv.exe or svchost.exe associated with Windows Update.