Log Injection
A cyberattack where malicious data is inserted into logs to mislead analysis or enable exploits.
Understanding Log Injection
Logging is a critical security mechanism used to track events, errors, and user activities. However, if user input is not properly sanitized before being recorded in log files, attackers can inject arbitrary content, including escape sequences and executable commands, leading to security risks.
How Log Injection Works
Manipulating Log Entries
Attackers inject specially crafted input that modifies log content.
Example: Logging a forged admin login attempt to create false audit trails.
Log Forging
Altering logs to mislead administrators and cover attack traces.
Example:
2025-02-09 12:30:00 [INFO] User: admin - Login Successful
Injecting a fake success message into logs can deceive security analysts.
Log Poisoning
Inserting malicious payloads into logs that may be executed later.
Example:
<?php system($_GET['cmd']); ?>
If an application later includes the log file via Local File Inclusion (LFI), this code may execute.
Challenges and Considerations
False Positives in Log Monitoring: Automated tools must balance security with operational accuracy.
Log Storage Management: Securing large-scale log repositories requires robust access control.
User Awareness & Training: Developers must follow secure logging practices to prevent injection risks.
Log Injection is a significant web security risk that can compromise forensic investigations and system integrity. Proper input validation and structured logging are essential to mitigating this threat.