How to Prevent Session Hijacking

Hackers can access a target’s computer or online accounts by using the session hijacking technique. A hacker who wants to acquire a user’s passwords and personal information hijacks the user’s browser session in a session hijacking attack. Session hijacking will be defined in this article along with its causes, symptoms, and methods of prevention.

What is a Session Hijacking Attack?

To get illegal access to a user’s session, hackers plan a session hijacking attack. They then take the victim’s identity and use it to their advantage for further exploitation. An attack vector takes advantage of the sessions that different services of an application create in order to maintain a connection to the server for the life of the current session. Sessions are used as a reference for a user’s initial authentication. Attackers deceive application servers into authenticating users by stealing a user’s session ID and applying it to their browser in order to accomplish this.

How Does Session Hijacking Work?

There are various methods a session hijacker can take over a user’s session. One popular technique is to intercept user and server communications using a packet sniffer, which enables the hacker to observe the data being delivered and received. They can then access private information or log into the account using this information.

Malware can also be used to hijack sessions by infecting the user’s PC. The hacker now has direct access to the computer and can hijack any running sessions.

Hijacking Attack Risk and Effects

A man-in-the-middle attack known as session hijacking gives the hacker complete control over a genuine user’s account and browser session if it is successful. The method, which has been around for years, entails thieves taking a legitimate session token from a user who is currently logged in before accessing the user’s account.

Attacks that hijack sessions may usually be prevented. In light of this, the application stack risks that account for a greater percentage of such attacks include:

  • Vulnerable components – Applications are more vulnerable to phishing attempts and man-in-the-middle attacks when insufficient security safeguards are not included into and maintained for third-party integrations and source code.
  • Predictable session token – Sensitive information linking the server and the user’s credentials is frequently found in some application session tokens and attributes in session cookies. One of the most popular techniques for successfully hijacking a session is for hackers to utilize automated tools to guess these session tokens.
  • Insufficient encryption – Without network traffic encryption after initial authentication, hackers can sniff session packets and intercept cookies sent between clients and servers by taking advantage of the TLS layer.
  • Malware – Malware that runs on a user’s device to hijack the session is installed by attackers on online apps with susceptible servers. The virus may engage in session sniffing, seize the temporary session cookie, and transmit it to the hacker for additional exploitation.

Depending on the importance of the application being accessed and the sensitivity of the data compromised, a session hijacking assault can pose a serious threat. A successful attack could have a variety of effects, including:

  • Financial fraud – Once they get control of financial systems, attackers can carry out transactions by pretending to be a legal user. For instance, they might access intellectual property, transfer money on behalf of the victim, or make purchases using information from an active session.
  • Identity theft – A typical assault technique entails obtaining a client’s login information, which enables the attacker to acquire unauthorized access to numerous accounts, elevate their privileges, and plan a full-scale attack.
  • Data breach – Attackers access a susceptible server’s sensitive data without authorization by using compromised sessions and logins. Once completed, attackers use this data to threaten to reveal personally identifying information and launch ransomware attacks against the organization or victims.
  • Exploiting Single Sign-On Systems (SSO) – Attackers can log in to other services that authenticate using SSO on systems that use SSO authentication by using an active session. It is more difficult to secure apps with unpredictable cookies and lax authentication methods since SSO systems often put the onus of session security on users.

Types of Session Hijacking Attacks and Examples

While there are several standards, resources, and best practices for protecting apps, the threat environment is constantly changing. Over the past year, hackers have developed a number of strategies to access a legitimate user’s session, including intricate attack patterns to plan the hijacking covertly.

A few examples of session hijacking attacks are:

1. Session Fixation Attacks

One of the most popular strategies takes advantage of the lack of encryption between the user and the distant server. The session hijacker searches the network for unencrypted traffic carrying session keys and tokens, intercepts it, and then uses the tokens to access targeted services while posing as the victim.

2. Cross-site scripting attacks

Cross-site scripting flaws are the most common targets of session hijackers when planning a takeover. Hackers do this while injecting client-side programs that grab session tokens. Attackers can create malicious Javascript code that gathers the session ID if the target server doesn’t set the HttpOnly property for session cookies.

Tricking consumers into clicking a malicious link to a well-known website that contains query parameters to transfer the user’s session key to the attacker’s web server is a common XSS attack technique for session hijacking. The URL argument for this attack, for instance, would resemble:

In this instance, the location.href command is used to send the document.cookie argument to the hijacker’s website after reading the session cookie. While using character encoding and URL shortening to conceal the malicious script within the link, real-world attacks are much more sophisticated and use these methods instead.

3. Brute Force

Once they understand that the server utilizes predictable IDs, the hackers use this strategy to guess and determine the session ID on their own. It is simple to guess session IDs generated by some business systems based on time, date, or the user’s IP address. Attackers frequently utilize session IDs from a known list, which only works when the session management platform is known to be vulnerable or when the session IDs are composed of a small number of widely used characters.

How to Prevent Session Hijacking

There are a number of strategies to avoid session hijacking:

  • Use strong passwords and multifactor authentication. In the event that hackers are successful in obtaining a user’s session ID, these strategies prevent accounts from being accessed..
  • Only share session IDs with trusted sources. When sending links or requests to websites, exercise caution because these actions may contain session IDs.
  • Use a VPN. A VPN makes it more difficult for attackers to steal session IDs by preventing them from intercepting traffic.
  • Keep software up to date. To stop attackers from using vulnerabilities to access users’ sessions, be sure to maintain operating systems and applications up to date with the most recent security patches.
  • Take cybersecurity training. Because cybersecurity threats are continuously changing, it’s important to keep up with the most recent attack methods and how to defend against them. Think about obtaining certifications in a variety of cybersecurity fields, such as ethical hacking, incident response, and penetration testing.


One of the riskiest cyberattacks is a session hijacking assault since it enables hackers to access a user’s account or data without authorization. Because it could lead to financial losses, reputational harm, legal responsibilities, etc., this attack could be very expensive.

In above article, you have learned how to prevent session hijacking. In our other blog post, we have also written many security tips for your website.

The final thing you also need to check is your web hosting provider. Make sure that your hosting provider has great security implementation on their system so your site wont be infected with Malware. At, we do keep maintain our security by keep updating our software and also our Anti Virus here.

George W
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