Listen to this Post
During an internal penetration test, a common yet dangerous misconfiguration was discovered: plaintext credentials stored in `web.config` files on an open share. This vulnerability allowed attackers to perform credential spraying, leading to further privilege escalation.
How the Attack Unfolded
- Discovery: The attacker found a `web.config` file containing plaintext credentials on an open network share.
- Credential Spraying: The exposed password was used in a spraying attack, compromising a second account.
- Privilege Escalation: The compromised account had local admin rights on a server, allowing lateral movement.
- Domain Admin Compromise: A scheduled task running a batch file as a Domain Admin was abused to add the attacker’s account to the Domain Admins group.
You Should Know: How to Detect & Prevent This
1. Detecting Plaintext Credentials in Web.config Files
Use PowerShell to scan network shares for sensitive files:
Get-ChildItem -Path "\Server\Share" -Recurse -Force -Include "web.config" | Select-String -Pattern "password=|connectionString="
2. Securing Web.config Files
- Encrypt Sensitive Sections: Use `aspnet_regiis` to encrypt credentials:
aspnet_regiis -pef "connectionStrings" "C:\Path\To\Website"
- Restrict File Permissions: Ensure only necessary users can access
web.config:icacls "C:\Path\To\web.config" /reset icacls "C:\Path\To\web.config" /grant "Administrators:(R)"
3. Monitoring for Credential Exposure
- Use Windows Event Logs: Monitor for unauthorized access:
Get-WinEvent -LogName "Security" -FilterXPath "[EventData[Data[@Name='AccessMask']='0x10000']"
- Deploy SIEM Rules: Alert on suspicious file access patterns.
4. Linux Equivalent: Scanning for Exposed Credentials
Use `grep` to search for sensitive data in configuration files:
grep -r "password=|api_key=" /var/www/
Secure file permissions:
chmod 600 /var/www/html/web.config
What Undercode Say
Storing credentials in plaintext is a critical security failure. Organizations must:
– Regularly audit file shares and configuration files.
– Enforce encryption for sensitive data.
– Restrict permissions to prevent unauthorized access.
– Monitor logs for credential misuse.
Failing to do so leads to rapid domain compromise, as attackers leverage exposed credentials for lateral movement and privilege escalation.
Expected Output
- PowerShell commands to detect and secure `web.config` files.
- Linux commands for credential scanning.
- Best practices for preventing credential exposure.
Prediction
As cloud and hybrid environments grow, misconfigurations exposing credentials will remain a top attack vector. Automated scanning tools and stricter DevSecOps practices will become essential to mitigate these risks.
References:
Reported By: Spenceralessi This – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
