This detection identifies a distributed botnet campaign attempting to compromise Point of Sale (POS) terminals through sustained Remote Desktop Protocol (RDP) brute-force attacks. Proactively hunting for this behavior in Azure Sentinel is critical because early identification allows the SOC team to isolate affected POS assets before credential theft leads to financial data exfiltration or ransomware deployment.
rule POS_bruteforcing_bot
{
meta:
maltype = "botnet"
ref = "https://github.com/reed1713"
reference = "http://www.alienvault.com/open-threat-exchange/blog/botnet-bruteforcing-point-of-sale-via-remote-desktop"
date = "3/11/2014"
description = "botnet bruteforcing POS terms via RDP"
strings:
$type="Microsoft-Windows-Security-Auditing"
$eventid="4688"
$data="\\AppData\\Roaming\\lsacs.exe"
condition:
all of them
}
This YARA rule can be deployed in the following contexts:
This rule contains 3 string patterns in its detection logic.
Here are 4 specific false positive scenarios for the botnet bruteforcing POS terms via RDP rule, including suggested filters and exclusions:
Scheduled Patch Management Deployment
10.20.50.0/24) during the defined maintenance window hours. Additionally, filter out events where the destination port is 3389 and the user account is a dedicated service account like svc-patch-agent.Remote Support for High-Volume Transaction Days
192.168.100.0/24) where the user context is an administrative group (Domain Admins or HelpDesk_Staff). Implement a threshold adjustment to allow up to 50 failed attempts per hour for these specific source