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Introduction:
In the high-stakes game of endpoint detection and response (EDR) evasion, knowledge of the security stack is power. A newly released open-source tool, CS-EDR-Enumeration, crystallizes this offensive principle by providing Cobalt Strike operators with a multifaceted toolkit to silently fingerprint security software on compromised Windows hosts. This tool transcends basic detection, offering a menu of techniques graded by operational risk, making it a significant asset for both sophisticated attacks and defensive security posture validation.
Learning Objectives:
- Understand the six core enumeration methods within CS-EDR-Enumeration and their associated “noise” levels.
- Learn how to execute and interpret both stealthy (BOF) and conventional (PowerShell) security product discovery.
- Grasp the tool’s application in purple teaming to benchmark and improve defensive telemetry and alerting.
You Should Know:
- The Philosophy of Operational Noise: Choosing Your Tradecraft
The tool’s core innovation is its explicit rating of each enumeration method. Operators must choose between stealth and comprehensiveness. A silent Beacon Object File (BOF) execution leaves minimal traces, ideal for a high-value target. A full PowerShell script might be noisier but provides richer data and is simpler to debug. This decision matrix forces operational discipline, simulating real-world attacker choices where triggering a behavioral alert could end an engagement.
Step‑by‑step guide:
- Load the `CS-EDR-Enumeration.cna` Aggressor script into your Cobalt Strike team server.
- In a Beacon console, use the `edr-enum` command to see the menu.
3. You will be presented with options like:
`1` – BOF (In-Process): Very Low Noise. Executes entirely within the Beacon process.
`4` – PowerShell: High Noise. Spawns `powershell.exe` and executes a script.
`6` – WMI: Medium Noise. Uses Windows Management Instrumentation queries.
4. Your choice should be based on your operational profile. Early reconnaissance might use option 1, while post-exploitation on a less-monitored host could use option 6 for more detail.
- Beacon Object File (BOF): The Silent In-Process Enumerator
This is the premier stealth option. A BOF is a C program compiled to a COFF object file, executed natively in the Beacon process’s memory via the `beacon_inline_execute` function. It does not create a new process, does not touch the disk (if executed correctly), and performs enumeration by calling native Windows APIs like those from `advapi32.dll` (Service Control Manager) directly.
Step‑by‑step guide:
- From the `edr-enum` menu, select option `1` (BOF).
- The tool will use the `service_enum_bof` function. Under the hood, it calls API sequences similar to:
// Pseudocode for service enumeration via OpenSCManager, EnumServiceStatus SC_HANDLE scm = OpenSCManager(NULL, NULL, SC_MANAGER_ENUMERATE_SERVICE); EnumServicesStatus(scm, SERVICE_WIN32, SERVICE_ACTIVE, ...);
- The results—process names, service names, and driver names—are cross-referenced against a embedded signature database (48 vendors, 199 processes, 115 services, 133 drivers) and printed directly to your Beacon console with minimal system impact.
-
Kernel Driver & Minifilter Detection: Finding the Deepest Hooks
Beyond userland processes and services, advanced EDRs install kernel-mode components, specifically minifilter drivers, to intercept file system, registry, and network operations at the lowest level. CS-EDR-Enumeration can enumerate loaded drivers and check their names against known EDR driver signatures. This reveals the most pervasive and difficult-to-evade components of the security product.
Step‑by‑step guide:
- The driver detection is integrated into several methods, most reliably in the BOF and native CMD/PowerShell enumerators.
- When executed, it runs a command equivalent to `fltmc instances` or enumerates drivers via the registry (
HKLM\SYSTEM\CurrentControlSet\Services\). - The output will list detected drivers, and the tool will flag any matching known EDR minifilter names (e.g.,
SysmonDrv,CarbonBlackFlt,CsAgent).
4. PowerShell & WMI: The Noisier Workhorses
These methods are louder but often more reliable and rich in detail. The PowerShell script (Invoke-EDREnum.ps1) can be run standalone, making it useful outside Cobalt Strike. It comprehensively checks processes, services, drivers, DLLs, and even registry uninstall keys. WMI uses the `Win32_Product` and `Win32_Service` classes, which are heavily monitored by advanced SIEMs.
Step‑by‑step guide for Standalone PowerShell:
1. Download the script from the GitHub repository.
- On a test Windows system (ideally in a lab), open an administrative PowerShell window.
3. Bypass execution policy if needed and run:
.\Invoke-EDREnum.ps1 -Method All
4. Review the colorful console output identifying security vendors. For a targeted check:
.\Invoke-EDREnum.ps1 -CheckFor "CrowdStrike", "Microsoft Defender"
- Purple Team Application: Turning an Offensive Tool into a Defensive Benchmark
This is where the tool shines for defenders. A purple team can use CS-EDR-Enumeration to systematically test their security monitoring. By executing each method (from low to high noise), the blue team can validate which techniques generate telemetry events in their EDR/XDR platform and which ones slip by silently. This gaps analysis drives detection engineering.
Step‑by‑step guide:
- Establish a Baseline: In a monitored lab environment, ensure your EDR/SIEM is actively logging.
- Execute Graded Enumeration: As the red team, run each of the six `edr-enum` methods from a simulated Beacon session.
- Correlate Alerts: The blue team reviews the SIEM/EDR console for related events: PowerShell logging (ScriptBlock/Module logging), WMI event subscriptions (
Event ID 5857), suspicious child processes ofbeacon.exe, or direct alerts on the enumeration activity. - Harden Detection: For silent methods that bypassed logging, create new detection rules. For example, hunt for `beacon.exe` making direct
OpenSCManager/EnumServiceStatusAPI calls outside normal user activity.
What Undercode Say:
- The Enumeration Arms Race is Over; Stealth Won. This tool formalizes what advanced adversaries already do: operate with surgical precision inside memory. Defenders can no longer rely on process creation logs as a primary source of truth.
- Purple Teaming is Non-Negotiable. The built-in noise rating makes this a perfect calibration tool. If your security stack doesn’t alert on the “High Noise” methods, you have a critical visibility gap.
The release of CS-EDR-Enumeration is less about a new capability and more about the democratization and standardization of advanced tradecraft. It packages research and techniques known to top-tier adversaries into a repeatable, accessible framework. For defenders, ignoring this tool’s implications is perilous. It serves as a concrete checklist for detection coverage. The underlying message is that post-exploitation fingerprinting has evolved from a loud, easily logged activity to a subtle art form conducted in the shadows of legitimate APIs and in-process execution. Security products must now lean heavily into behavioral analytics and kernel-level telemetry to spot these activities, moving beyond simple signature-based alerts for known enumeration tools.
Prediction:
Within the next 12-18 months, the principles embedded in CS-EDR-Enumeration will force a significant shift in EDR design and defensive strategies. We will see a surge in EDR solutions offering “silent” or “memory-only” protection modes that minimize their own fingerprintable footprint. Concurrently, defensive detection will pivot further towards canary-style deception (honeypot services, fake driver names) and advanced behavioral models that flag the context and sequence of otherwise legitimate API calls, rather than just their occurrence. The line between offensive tooling and defensive benchmarking tools will continue to blur, with the most effective security teams adept at wielding both.
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Reported By: Daniel Feichter – Hackers Feeds
Extra Hub: Undercode MoN
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