---
id: e57837f0-4b1f-4737-b2bd-463c6ca4eb02
---

# ETag Header Server Information Leak Protection for Nginx Server.
---

This incident type involves protecting an Nginx server from Server Information Leak through the use of ETag header. This is done to prevent sensitive server information from being disclosed to unauthorized parties. The ETag header allows for the identification of resources that have changed. By protecting the ETag header, the server can prevent attackers from gaining access to sensitive information that could potentially be used to compromise the server or its resources.

### Parameters
```shell
export NGINX_ACCESS_LOG_FILE="PLACEHOLDER"

export NGINX_ERROR_LOG_FILE="PLACEHOLDER"

export NGINX_SERVER_URL="PLACEHOLDER"

export NGINX_CONFIG_FILE="PLACEHOLDER"
```

## Debug

### Check if the Nginx server is running.
```shell
systemctl status nginx
```

### Check the Nginx configuration file for the Etag header.
```shell
cat ${NGINX_CONFIG_FILE} | grep etag
```

### Check the Nginx access logs for signs of Etag header leaks.
```shell
cat ${NGINX_ACCESS_LOG_FILE} | grep -i etag
```

### Check the Nginx error logs for any related errors.
```shell
cat ${NGINX_ERROR_LOG_FILE} | grep -i etag
```

### Use curl to check if the server is leaking Etag header information.
```shell
curl -I ${NGINX_SERVER_URL}
```

## Repair

### Disable ETag header in the Nginx server configuration file to prevent its disclosure.
```shell
bash

#!/bin/bash



# Stop the Nginx service

sudo systemctl stop nginx.service



# Edit the Nginx configuration file to disable the ETag header

sudo sed -i 's/etag on;/etag off;/g' ${NGINX_CONFIG_FILE}



# Start the Nginx service

sudo systemctl start nginx.service


```

This incident type involves protecting an Nginx server from Server Information Leak through the use of ETag header. This is done to prevent sensitive server information from being disclosed to unauthorized parties. The ETag header allows for the identification of resources that have changed. By protecting the ETag header, the server can prevent attackers from gaining access to sensitive information that could potentially be used to compromise the server or its resources.


```shell
export NGINX_ACCESS_LOG_FILE="PLACEHOLDER"

export NGINX_ERROR_LOG_FILE="PLACEHOLDER"

export NGINX_SERVER_URL="PLACEHOLDER"

export NGINX_CONFIG_FILE="PLACEHOLDER"
```


### Check if the Nginx server is running.

```shell
systemctl status nginx
```

### Check the Nginx configuration file for the Etag header.

```shell
cat ${NGINX_CONFIG_FILE} | grep etag
```

### Check the Nginx access logs for signs of Etag header leaks.

```shell
cat ${NGINX_ACCESS_LOG_FILE} | grep -i etag
```

### Check the Nginx error logs for any related errors.

```shell
cat ${NGINX_ERROR_LOG_FILE} | grep -i etag
```

### Use curl to check if the server is leaking Etag header information.

```shell
curl -I ${NGINX_SERVER_URL}
```


### Disable ETag header in the Nginx server configuration file to prevent its disclosure.

```shell
bash

#!/bin/bash



# Stop the Nginx service

sudo systemctl stop nginx.service



# Edit the Nginx configuration file to disable the ETag header

sudo sed -i 's/etag on;/etag off;/g' ${NGINX_CONFIG_FILE}



# Start the Nginx service

sudo systemctl start nginx.service


```


ETag Header Server Information Leak Protection for Nginx Server.

Overview

Parameters

Debug

Check if the Nginx server is running.

Check the Nginx configuration file for the Etag header.

Check the Nginx access logs for signs of Etag header leaks.

Use curl to check if the server is leaking Etag header information.

Repair

Disable ETag header in the Nginx server configuration file to prevent its disclosure.

Learn more

Related Runbooks

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