Hijacking: Definition, Types, How It Works, and How to Prevent It

Imagine your company’s internal system being accessed by an unauthorized party with no login alerts, no suspicious activity flags, and no warnings from your security tools whatsoever. By the time the IT team realizes what happened, customer data has already been compromised and the damage is done.

This is exactly how hijacking incidents often unfold in corporate environments. The attack does not always arrive with obvious warning signs. In fact, it tends to operate silently behind a system that appears to be functioning normally.

What Is Hijacking?

Hijacking, in the context of cybersecurity, refers to unauthorized takeover of a system, network, browser, or active user session by a malicious party. Unlike attacks that cause immediate visible destruction, hijacking works by “riding on” existing access without the victim ever knowing.

The term comes from the word hijack, meaning the act of taking control of something by force or deception. In the digital world, the meaning remains the same: something is stolen or taken over illegally. Targets can range from active accounts and network connections to browsers and company-owned website domains.

Types of Hijacking Attacks

Hijacking is not a single technique. It comes in several variants, each exploiting a different vulnerability within your digital infrastructure.

1) Session Hijacking

Session hijacking occurs when an attacker steals a session token used by a logged-in user to stay authenticated on a platform. With that token, the attacker can access the victim’s account without ever needing their username or password.

2) Browser Hijacking

In browser hijacking, a user’s web browser settings are altered without their knowledge, from the homepage to the default search engine. Users often do not notice the change until they are redirected to a malicious site or start seeing unusual advertisements.

3) DNS Hijacking

DNS hijacking manipulates the domain resolution process so that users who type a legitimate website address are redirected to a fake site. This technique is commonly used to steal login credentials through a counterfeit page that looks visually identical to the real one.

4) Clickjacking

Clickjacking conceals malicious elements beneath a normal-looking interface, causing users to unknowingly click on something different from what they see. This technique is often used to activate camera or microphone permissions, or to trigger fund transfers without the user’s consent.

5) Account Hijacking

Account hijacking is the full takeover of an account through methods such as phishing, credential stuffing, or brute force. Once inside, the attacker can modify account information, lock out the original owner, or use the account to carry out further crimes.

Comparison Table:

How Hijacking Works

Despite their variations, most hijacking attacks follow a similar general pattern. Here is a step-by-step breakdown of how attackers typically operate:

1. Reconnaissance
   The attacker identifies a target and looks for vulnerabilities, such as unencrypted public Wi-Fi, outdated browsers, or accounts without two-factor authentication.
2. Interception or Injection
   In session hijacking, for example, when an employee logs into a company’s internal system over an unsecured network, an attacker on the same network can capture the session token sent by the browser. That token alone is enough to gain access without knowing the password.
3. Access Takeover
   In a DNS hijacking scenario, a user types the correct banking website address into their browser. But because the DNS server has been manipulated, they are redirected to a counterfeit page with an identical design. The moment they enter their credentials, that login data goes straight to the attacker.
4. Exploitation
   The hijacked access is then used to steal data, alter records, move funds, or launch further attacks against other targets deeper within the same network.
5. Covering Tracks
   Attackers typically delete or manipulate activity logs to complicate investigation and slow down the security team’s response.

The Business Impact of Hijacking

Hijacking is far from a problem that IT teams can handle alone.

According to a report released by BSSN (Indonesia’s National Cyber and Crypto Agency) in early 2023, total cybersecurity traffic anomalies across Indonesia throughout 2022 reached 976 million incidents, with data leaks (information leak) accounting for 14.75 percent of all recorded attack types.

The reported financial loss from cyberattacks in Indonesia that same year reached IDR 14.5 trillion, and the real figure is believed to be even higher since many incidents go unreported. For businesses that fall victim, the consequences can be far-reaching:

• Customer data breaches that lead to legal action or permanent loss of public trust
• Direct financial losses from unauthorized transactions carried out while accounts or systems are under attacker control
• Regulatory compliance risks under Indonesia’s Personal Data Protection Law (UU PDP No. 27/2022), where companies that fail to protect user data may face administrative sanctions or criminal liability

Warning Signs Your System Is Being Hijacked

Detecting hijacking early depends heavily on the type of attack, since each one leaves a different kind of footprint. Here are the warning signs to watch for, broken down by attack type:

• Signs of Session Hijacking
  An account suddenly shows activity (sent messages, changed data, transactions) that the actual owner did not perform. System logs record simultaneous active sessions from two different locations or devices.
• Signs of Browser Hijacking
  The browser homepage or default search engine changes without the user doing anything. The browser starts displaying unusual ads, or every link click redirects to an unrelated site.
• Signs of DNS Hijacking
  A website unexpectedly prompts the user to log in again despite the session still being active. The SSL security certificate appears invalid or different from usual, which is a sign that the page being visited is not the real one.
• Signs of Clickjacking
  Users report actions that “happen on their own,” such as camera or microphone permissions activating without any deliberate input. Buttons or links on a page behave in a way that does not match what is displayed.
• Signs of Account Hijacking
  Password reset or account change notification emails arrive without the owner requesting them. The user is suddenly unable to log in because their credentials have been altered by an unauthorized party.

How to Prevent Hijacking Attacks

Not every prevention measure applies universally to all types of hijacking. Some steps are general best practices, while others are specific to particular attack variants.

General prevention (applies to all types of hijacking):

• Enable two-factor authentication (2FA) on all important accounts and systems. Even if an attacker obtains login credentials, 2FA acts as an additional barrier against unauthorized access.
• Keep all software up to date, including operating systems and browsers. Many hijacking methods exploit known vulnerabilities in outdated versions that have already been publicly documented.
• Monitor access logs consistently to detect anomalies early, such as logins from unusual locations or at unexpected times.

Type-specific prevention:

• How to Prevent Session Hijacking
  Apply the HttpOnly and Secure attributes to cookies to prevent session tokens from being read or stolen via cross-site scripting (XSS) attacks. Implement session token rotation so that any stolen token expires quickly.
• How to Prevent Browser Hijacking
  Only install browser extensions from official and trusted sources. Conduct regular audits of installed extensions on work devices, as malicious extensions are one of the primary vectors for this attack type.
• How to Prevent DNS Hijacking
  Use DNS over HTTPS (DoH) or DNS over TLS (DoT) to encrypt DNS requests and make them harder to manipulate. Enable DNSSEC to verify the authenticity of DNS responses received.
• How to Prevent Clickjacking
  Add the [X-Frame-Options: DENY] or [Content-Security-Policy: frame-ancestors ‘none’] security header to your web server. This prevents your site’s pages from being loaded inside an iframe by a third party, which is the primary mechanism behind clickjacking.
• How to Prevent Account Hijacking
  Enforce rate limiting policies on login attempts to block brute force attacks, and use a centralized access management platform to monitor all authentication activity in real time.

Conclusion

Hijacking is a threat that does not discriminate by business size. Small companies and large corporations are equally at risk, especially when access management and digital risk oversight are still handled manually or in fragmented systems.

Understanding the different types is an important first step, but what matters far more is having a system capable of monitoring, documenting, and responding to risks on a consistent basis.

Adaptist Prime, the GRC platform from Adaptist Consulting, is built to help organizations manage data security risks in a structured way, from digital asset mapping to UU PDP compliance monitoring, all within a single integrated dashboard.

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