Nginx security issues and countermeasures

Nginx is a lightweight, high-performance and scalable web server and reverse proxy software. It is widely used in the architecture of Internet applications because of its stability and flexibility. However, as a network service program, there are security issues at any time. We need to actively respond to and improve Nginx's security risks.

1. Security issues in Nginx

1. File inclusion vulnerability: Nginx supports SSI syntax (Server Side Include) which can directly introduce the contents of other files. If these files have security vulnerabilities, they may will pose a threat to the entire system.

2. Cache fraud: Nginx’s caching function can speed up page response, but there is also the risk of being maliciously exploited by attackers. For example, attackers can construct specific URLs to tamper with the data stored in the cache file. Or to be hijacked.

3. Cross-site scripting attack: The attacker injects malicious scripts during operations such as submitting a form or submitting a comment, thereby obtaining the user's sensitive information or causing other security issues.

4.DDoS attack: As a web server and reverse proxy, Nginx cannot avoid DDoS attacks. Attackers use a large number of connection requests to occupy Nginx's processing power, causing the website to paralyze.

2. Nginx security response strategy

1. Restrict file access: disable or limit Nginx’s SSI syntax or specific file access methods to prevent malicious users from using file inclusion vulnerabilities to obtain sensitive information or attack system.

2. Strengthen cache security: limit the size and time of cache files, and set verification rules (such as ETag) to verify whether the data has been tampered with. Cache fraud protection can also use methods such as adding timestamps and request time parameters to the cache to increase the difficulty for attackers to tamper with the cache.

3. Filter requests: Configure rules on Nginx to filter out illegal requests, such as empty requests, virus requests, malicious requests, etc.

4. Prevent SQL injection and XSS attacks: By configuring output filtering rules, perform legality verification and filtering of input parameters.

5. Improve skills in responding to DDoS attacks: use Nginx as the core to implement a scalable reverse proxy architecture; use hardware protection equipment and reduce useless access traffic to avoid external attacks.

6. Update the software regularly: Nginx releases new versions and will fix some security vulnerabilities, so the software needs to be updated frequently, especially when deploying Nginx on a VPS.

In the process of using Nginx, security issues are always a topic that requires constant attention. Only by taking preventive measures can we better protect the data security of applications and users.

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