April 6th, 2022 
Server Security – Issues and Best Practices
ITC 766-899
WEB APPLICATION SECURITY
Spring 2022
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Outline
Intro to Server Security
Need for Server Security
Server Security Fundamentals
Server Security Issues
OWASP Top 10 – A6:2017– Security Misconfiguration
OWASP Top 10 – A10:2017– Insufficient Logging and Monitoring
Attacks against Server Security Mechanisms
Server Security Best Practices
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Intro to Server Security
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Intro to Server Security
How does a web application work?
Client
Server
Involves servers
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Server
A server serves as the host for web applications
It refers to the “server” portion of the client-server architecture
It receives the HyperText Transfer Protocol (HTTP) request message from the client machine’s browser
It authenticates the client based on the user-supplied credentials
It authorizes the client’s access to the requested web application after authentication
Intro to Server Security (contd.)
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Server (continued)
It sends an HTTP response header back to the client machine with the response code 200 for successful requests or the response code 404 for page not found (maybe due to a broken link)
It uses ports to make services available to clients
Common port numbers: 80 for HTTP traffic, 443 for HTTPS traffic, 25 for SMTP traffic, 21 for FTP traffic, 23 for telnet traffic, etc.
Examples:
Apache HTTP Server, Apache Tomcat, Microsoft IIS, IBM WebSphere, Oracle WebLogic, Red Hat JBoss EAP, etc.
Intro to Server Security (contd.)
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Server Market Share:
Intro to Server Security (contd.)
Source: Web and Application Servers Market Share Report – Datanyze –
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What is a Server? – PowerCert Animated Videos
Intro to Server Security (contd.)
Source: PowerCert Animated Videos – What is a Server? –
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Server security refers to “the fundamental activities performed as part of securing and maintaining the security of servers that provide services over network communications as a main function” ()
Server security involves the following ():
Installing, configuring, and securing the server Operating System (OS)
Installing, configuring, and securing the server software
Employing appropriate network protection mechanisms
Firewalls, packet filtering routers, proxies, etc.
Ensuring that the hosted web applications are securely coded
Employing secure administration and maintenance processes
Patching and upgrading, testing, monitoring of logs, backing up data and OS
Protecting information and data in a careful/systemic manner
Conducting initial/periodic vulnerability scans of server/network infrastructure
Intro to Server Security (contd.)
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Server security (by technology):
security settings
security settings
security settings
security settings
security settings
Server security (by Operating System)
guide
security guide
Guide
Intro to Server Security (contd.)
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Need for Server Security
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As per :
Servers are frequently targeted by attackers because of the value of their data and services
Servers might contain personally identifiable information that could be used to perform identity theft
Most organizations install servers with standard directory names, directory locations, and filenames making it easy for attackers to target those servers
The failure of organizations to fully recognize the amount of expense and skills required to field a secure server often results in overworked employees and insecure systems
Need for Server Security
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As per (continued):
Default hardware and software configurations are typically set by manufacturers to emphasize features, functions, and ease of use, at the expense of security
The default configuration of the OS often includes guest accounts (with and without passwords), administrator or root level accounts, and accounts associated with local and network services
Because manufacturers are unaware of each organization’s security needs, server administrators need to configure new servers to reflect their organizations’ security requirements and reconfigure them as needed
Need for Server Security (contd.)
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As per :
Compromised web sites can serve as an entry point for intrusions into many organizations’ internal networks
Organizations can face monetary losses, damage to reputation, or legal action if an intruder successfully violates the confidentiality of their data
Hackers could compromise web server security by:
defacing organizations’ web site or otherwise affecting integrity
executing unauthorized commands on the host OS
launching attacks on external sites from the web server
using the server to deliver attacks against vulnerable clients
using the server to distribute illegally copied software
Need for Server Security (contd.)
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As per the Vulnerability Statistics Report, the most common infrastructure vulnerabilities include the following server-related issues:
44.70% – SSL / TLS Version & Configuration Issues
29.53% – SMB Security Issues
8.61% – OpenSSH Vulnerabilities & Configuration Issues
6.25% – Windows Remote Desktop Protocol Server MITM
4.15% – Unencrypted Telnet Services
1.69% – Unsupported & Unpatched Server Detection
Need for Server Security (contd.)
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As per the Vulnerability Statistics Report:
33.33% of all high and critical risk vulnerabilities discovered in 2018 were in relation to unsupported Windows Server 2003 systems (no patching, support, end-of-life systems)
7.53% of all high and critical risk vulnerabilities discovered in 2018 related to exposure to CVEs (, ) – Windows Server Message Block (SMB) Remote Code Execution Vulnerability
Systems using Apache and PHP also contributed to the Top 10 due to weak component security and traditional patch management of exposed systems
Need for Server Security (contd.)
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Hackers are increasingly using servers to cause data breaches ()
Need for Server Security (contd.)
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Server Security Fundamentals
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What is the Apache HTTP Server? – CBT Nuggets
Server Security Fundamentals
Source: CBT Nuggets – What is the Apache HTTP Server? –
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A basic Apache web server architecture includes the following components ():
Modules
Multi-Processing Modules (MPM)
Apache Portable Runtime (APR) Libraries
Server Security Fundamentals (contd.)
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Apache web server architecture:
Functionality that can be used to do things such as authentication, dynamic content generation, encryption, virus scanning, file compression, email services, file transfer services, etc.
Special module which allows Apache to be configured as a pure process-based server, a pure threaded server, or both
Provides for platform-specific tuning and optimization
Server Security Fundamentals (contd.)
Source: Apache – Apache HTTP Server Version 2.4 Documentation –
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Apache web server security:
Modular architecture
Allows modules to be enabled or disabled to add and remove web server functionality
Only MPM modules can interact directly with the Operating System
Authentication
Modules can authenticate against plain text files and database files including Oracle, MySQL, PostgreSQL, etc.
E.g. , , , , etc.
Server Security Fundamentals (contd.)
Source: Apache – Apache HTTP Server Version 2.4 Documentation –
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Apache web server security (continued):
Access Control
The module can restrict access to resources based on IP address or hostname of the client
SSL / TLS
The module provides strong encryption to protect data transmitted between the web server and the client
Proxy
Apache supports both a traditional HTTP proxy and a reverse proxy
Reverse proxy can be used for load balancing
Virtual Hosting Support and Security
Server Security Fundamentals (contd.)
Source: TLDP.org – Apache Overview HOWTO –
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Apache web server security (continued):
Configuration Settings
Modules come with several directives related to timeouts, resource consumption, request processing, concurrent connections, etc.
Common Gateway Interface (CGI) & Server Side Includes (SSI)
The suEXEC feature can reduce considerably the security risks involved with allowing users to develop and run private CGI or SSI programs
Logs
The , modules can be used to log everything that happens on the server
Server Security Fundamentals (contd.)
Source: Apache.org – Apache HTTP Server Documentation Version 2.4 –
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Server Security Issues
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As per (pg. 7), server security issues include:
Server Security Issues
Source: NIST SP 800-123 – Guide to General Server Security –
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As per (pg. 17-18), other server security issues include the following:
Misconfiguration or other improper operation of the Web server, which may result, for example, in the disclosure or alteration of proprietary or sensitive information. This information can include items such as:
Assets of the organization
Configuration of the server or network that could be exploited for subsequent attacks
Credentials of the users or administrator(s) of the Web server
Inadequate or unavailable defense mechanisms for the Web server to prevent certain classes of attacks, such as DoS attacks, which disrupt the availability of the Web server and prevent authorized users from accessing the Web site when required
Server Security Issues (contd.)
Source: NIST SP 800-44 – Guidelines on Securing Public Web Servers –
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Other server security issues include the following (continued):
Vulnerabilities within the Web server that might allow, for example, attackers to compromise the security of the server and other hosts on the organization’s network by taking actions such as the following:
Server Security Issues (contd.)
Source: NIST SP 800-44 – Guidelines on Securing Public Web Servers –
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OWASP Top 10–A6:2017 – Security Misconfiguration
Server Security Issues (contd.)
Source: OWASP Top 10 2017 A6 – Security Misconfiguration –
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Common server security vulnerabilities:
Server Security Issues (contd.)
Source: OWASP Top 10 2017 A6 – Security Misconfiguration –
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OWASP Top 10–A10:2017 – Insufficient Logging & Monitoring
Server Security Issues (contd.)
Source: OWASP Top 10 2017 A10 – Insufficient Logging & Monitoring –
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Common server security vulnerabilities:
Server Security Issues (contd.)
Source: OWASP Top 10 2017 A10 – Insufficient Logging & Monitoring –
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Server Security Attacks
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Most common server security attacks:
Server Security Attacks
| Attack Type | Description |
| Denial of Service (DoS) | Attacks may be directed to the server or its supporting network infrastructure, denying or hindering valid users from making use of its services.Attacks may take advantage of the server’s account lockout policy.Attacks may involve uploading many large filesAttacks take advantage of simultaneous network connections. |
| Malware | Malicious entities may gain unauthorized access to resources elsewhere in the organization’s network via a successful attack on the server |
Source: NIST SP 800-123 – Guide to General Server Security –
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Most common server security attacks (continued):
Server Security Attacks (contd.)
| Attack Type | Description |
| Man-in-the Middle (MITM) | Password information can be intercepted using network sniffers and used by an attacker to masquerade as an authorized user |
| SYN Flood | If the maximum number of open connections (or connections that are half-open—that is, the first part of the TCP handshake was successful) is set to a low number, an attacker can easily consume the available connections with illegitimate requests (often called a SYN flood) |
Source: NIST SP 800-123 – Guide to General Server Security –
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Most common server security attacks (continued):
Server Security Attacks (contd.)
| Attack Type | Description |
| Brute Force | Attackers try every possible password to attempt to gain access to a user’s account |
| Command Injection | Compromise of sensitive information on backend databases that are used to support a web application |
| Directory Traversal | Unauthorized access including gaining access to files or folders and being able to execute commands and/or install software on the web server |
| Replay Attack | An impostor verifier replays the OTP authenticator output to the verifier and successfully authenticates to the web server (NIST SP 800-63b) |
Source: NIST SP 800-44 – Guidelines on Securing Public Web Servers –
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Replay Attacks – Professor Messer
Server Security Attacks (contd.)
Source: Replay Attacks – CompTIA Security+ Sy0-401: 3.2 –
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Server Security Best Practices
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Server Security Best Practices
Best practices for web server security include :
Planning and managing web servers (pg. 33)
Plan the configuration and deployment of the web server
Choose an appropriate Operating System (OS) for the web server
Choose an appropriate platform for the web server
General purpose OS, Trusted OS, web server appliance, virtualized platform, etc.
Securing the web server OS (pg. 41)
Patch and upgrade the OS
Remove or disable unnecessary services and applications
Configure OS user authentication
Configure resource controls appropriately
Install and configure additional security controls
Test the security of the OS
Source: NIST SP 800-44 – Guidelines on Securing Public Web Servers –
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Server Security Best Practices (contd.)
Best practices for web server security include :
Securing the web server (pg. 51)
Securely install the web server
Configure IS and web server access controls
Configure a secure web content directory
Securing web content (pg. 70)
Ensure that sensitive information is not available on the web server
Establish an organizational-wide documented formal policy and process for approving public web content
Maintain Web user privacy
Mitigate indirect attacks on content
Consider client-side active content security
Maintain server-side active content security
Source: NIST SP 800-44 – Guidelines on Securing Public Web Servers –
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Server Security Best Practices (contd.)
Best practices for web server security include :
Using authentication and encryption technologies (pg. 86)
Configure web authentication and encryption technologies
Configure SSL / TLS
Protect against brute force attacks
Implementing a secure network infrastructure (pg. 99)
Identify a network location
Assess firewall configuration
Evaluate intrusion detection and prevention systems
Assess network switches
Evaluate load balancers
Evaluate reverse proxies
Source: NIST SP 800-44 – Guidelines on Securing Public Web Servers –
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Server Security Best Practices (contd.)
Best practices for web server security include :
Administering the web server (pg. 113)
Perform logging
Perform web server backups
Recover from a compromise
Test security
Conduct remote administration and content updates
Source: NIST SP 800-44 – Guidelines on Securing Public Web Servers –
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Use the following server security best practices to protect against security misconfiguration:
Server Security Best Practices (contd.)
Source: OWASP Top 10 2017 A6 – Security Misconfiguration –
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Use the following server security best practices to protect against insufficient logging and monitoring:
Server Security Best Practices (contd.)
Source: OWASP Top 10 2017 A10 – Insufficient Logging & Monitoring –
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Server security issues continue to be among the OWASP Top 10 list of web application security risks
This is due to weaknesses in server technologies such as authentication, access controls, configuration, connections, encryption, active content, logs, etc.
Hackers are able to exploit the weaknesses using attacks such as DoS, malware, MITM, SYN flood, brute force, command injection, directory traversal, replay attacks, etc.
Best practices to protect servers include planning and managing web servers, securing the web server OS, securing the web server, securing web content, using authentication and encryption technologies, implementing a secure network infrastructure, administering the web server, etc.
Recap
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Thank you!!!
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