This tweet highlights several security issues related to web application firewalls (WAFs), focusing on a hardcoded, self-made WAF that uses well-known regular expressions for filtering. The main points mentioned include:
1. User Enumeration: Attackers may be able to determine valid users in the system, which is a preliminary step that can aid in further attacks like SQL injection.
2. Raw SQL Implementation (SQL Injection): The system is vulnerable to SQL Injection attacks, where attackers can execute arbitrary SQL queries via user inputs.
3. Hardcoded Self-Made WAF: The WAF is custom-built and uses well-known regex patterns to block attacks. However, since these patterns are widely known, most attackers can bypass the WAF.
4. Limited Updates: Because the WAF is hardcoded, it is less likely to receive updates to handle modern attack techniques, making it increasingly vulnerable over time.
In summary, the use of a homemade, regex-based WAF imposes serious security risks. Attackers can easily bypass it using known techniques, leading to user enumeration and SQL injection vulnerabilities. This highlights the importance of using regularly updated, robust security solutions rather than relying on hardcoded protections.
For more details, check out the original tweet here: https://twitter.com/rival_rvdt/status/1939352257528762733