Web Server Hardening - Apache


1. Secure Apache Configuration with .htaccess


1.1 OWASP A3:2017-Sensitive Data Exposure

Turn ETags Off
FileETag None

The ETag value is used in cache management to save network bandwidth. *

 e.g. ETag: "16793-106a-4e71be79cdd80"

 File's i-node number: 16793 (Hex)  = 92051 (Dec)
File size (Bytes): 106a (Hex)  = 4202 (Dec)
File modification time: 4e71be79cdd80 (Hex) / 1380006942793088 (Dec or Epoch) / September 24, 2013 7:15:42 (GMT)

To print i-node number for a file
ls -i <filename>

Best Hex to Decimal Converter Online: https://codebeautify.org/hex-decimal-converter
Epoch & Unix Timestamp Conversion Tools: https://www.epochconverter.com

1.2 OWASP A5:2017-Broken Access Control

Brute Force Directories and Files names



Restrict Access to Directory
  1. Create passwords for .htpasswd files using Htpasswd Generator
  2. Copy the text generated into .htpasswd file
AuthName "Unauthorized access is prohibited."
AuthUserFile </home/yourdirectory/.htpasswd>
AuthGroupFile /dev/null
AuthType basic
require user <putyourusernamehere>


1.3 OWASP A6:2017 - Security Misconfiguration

Disable Directory Listing
Options -Indexes
Directory Listing

Prevent Access to Certain File Types for Protected Directories
<FilesMatch "\.(inc)$"> 
Order Deny,Allow
Deny from all
</FilesMatch>

.inc file can be accessed before the implementation of code

2. Secure Apache Configuration with httpd.conf

C:\xampp\apache\conf\httpd.conf

2.1 OWASP A3:2017-Sensitive Data Exposure

2.1.1 Limiting Information provided by Apache Web Server

HTTP Response Header

Server-generated Document

Nmap result before the configuration in httpd.conf

ServerTokens Prod  #Product Only
ServerSignature Off #After version 2.0.44, the details of the server version number presented are controlled by the ServerTokens directive

Reference:
https://httpd.apache.org/docs/current/mod/core.html#servertokens
https://httpd.apache.org/docs/current/mod/core.html#serversignature

Nmap result after the configuration in httpd.conf

Wappalyzer not able to retrieve the version of Apache after ServerTokens Prod is set


Apache Server Information

Apache /server-info is enabled
Do not load mod_info module 
#LoadModule info_module modules/mod_info.so

2.1.2 Transport Layer Protection
Configuration File: C:\xampp\apache\conf\extra\httpd-ssl.conf

A) Redirect every page to HTTPS

Asking the client to fetch https:// URL

<virtualhost>
Redirect permanent / https://192.168.24.2/ #Returns a permanent redirect status (301) indicating that the resource has moved permanently
</virtualhost>

Reference: https://httpd.apache.org/docs/current/mod/mod_alias.html#redirect

B) Server Protocol and Cipher Configuration 
SSLProtocol -ALL +TLSv1.2 #Only TLSv1.2 will be accepted
SSLCipherSuite EDH+CAMELLIA:EDH+aRSA:EECDH+aRSA+AESGCM:EECDH+aRSA+SHA256:EECDH:+CAMELLIA128:+AES128:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!DSS:!RC4:!SEED:!IDEA:!ECDSA:kEDH:CAMELLIA128-SHA:AES128-SHA

sslscan result after the implementation of secure protocol and cipher 

Reference:
https://httpd.apache.org/docs/2.4/mod/mod_ssl.html#sslprotocol
https://httpd.apache.org/docs/2.4/mod/mod_ssl.html#sslciphersuite

2.2 OWASP A6:2017 - Security Misconfiguration

Disable TRACE Method
TraceEnable Off

TRACE enabled


We can try to make use of TRACE/TRACK method to read the cookie information in HTTP headers. To understand better with XST, please read the article Penetration Testing with OWASP Top 10 - 2017 A7 Cross-Site Scripting (XSS).

TRACE disabled



ModSecurity

Installation on Windows

1. Download mod_security from https://www.apachelounge.com/download/
2. Extract mod_security.zip
3. Copy libcurl.dll and yajl.dll into C:\xampp\apache\bin folder
4. Copy mod_security2.so into C:\xampp\apache\modules folder
5. Enable security2_module in httpd.conf
LoadModule security2_module modules/mod_security2.so
6. Enable unique_id module in httpd.conf by uncommenting 
LoadModule unique_id_module modules/mod_unique_id.so

Write a Testing Ruleset

1. Write ruleset in in httpd.conf
Method 1
<IfModule security2_module> 
SecRuleEngine On
SecDefaultAction "deny,phase:2,status:403"
SecRule ARGS "\.\./" "t:normalizePathWin,id:50904,severity:4,t:none,t:urlDecodeUni,t:htmlEntityDecode,t:lowercase,msg:'Drive Access'" 

SecServerSignature "Keepitsecret/6.0" 
</IfModule>

Method 2
<IfModule security2_module> 
Include modsecurity.d/modsecurity.conf
</IfModule>

In C:\xampp\apache\modsecurity.d\modsecurity.conf 

SecRuleEngine On
SecDefaultAction "deny,phase:2,status:403"
SecRule ARGS "\.\./" "t:normalizePathWin,id:50904,severity:4,t:none,t:urlDecodeUni,t:htmlEntityDecode,t:lowercase,msg:'Drive Access'" 

SecServerSignature "Keepitsecret/6.0"

2. Browse a local web page with file inclusion payload to test whether ModSecurity works

Access forbidden once the payload meet the rule set and server signature is changed

3. Check error.log for more information


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