When pirates try to board another ship, they make it pretty clear they intend to steal everything on board and steer it wherever they want. The same goes in military operations, when an enemy army tries to seize control of an aircraft or a train.
If only it were that obvious when cybercriminals try to take over your web browser. Instead, session hijacking can easily fly under the radar – and they may manage to steal your data or even money before you realize what happened.
What Is Session Hijacking?
Definition and explanation of session hijacking
Session hijacking is a cyberattack whereby rogue actors gain access to a system or application when the victim is connecting online for a legitimate purpose.
You could be logging into a business application at work, for example, or shopping online during your lunch hour. The attack could also occur when you’re accessing your banking portal to check your account balances.
Regardless of what you’re doing while connected, session hijacking allows third parties to exploit the control mechanism, such as a session token. This lets cybercriminals impersonate their victims and either steal information, perform unauthorized actions or spawn further attacks.
What is a session?
Before we explain session hijacking, let’s talk about sessions.
A session is the length of time you spend interacting with a website or application. For example, when you shop on Amazon, your session begins when you log in and ends when you log out. You get a unique session ID or identifier for each login.
Your session can also end if there’s a period of inactivity. Let’s say you head to the kitchen to fix yourself a sandwich. When you return after 15 minutes, your session has expired, and Amazon has logged you out. If you log in again and begin putting items in your cart, Amazon counts this as a new session.
Amazon uses session IDs to manage multiple sessions simultaneously. Session data is stored on Amazon servers. This helps Amazon remember your shopping cart contents, display relevant product recommendations, show your recently viewed items, and note your language, payment, and delivery preferences.
Different types of session hijacking
Cybercriminals can hijack your web session in one of two ways, but both have damaging consequences.
In passive hijacking, for example, threat actors will quietly monitor the traffic between their prospective victim’s computer and a server. Think of it as a form of digital eavesdropping.
Attackers may not take over the session and perform any actions as though they were victim in this case. The main purpose here is to gather information and potentially steal data. This could include credentials like passwords to other applications.
Active hijacking is more of an overt attempt to bypass the security of an authenticated session and essentially silence the victim’s computer. Cybercriminals can then issue commands, like opening additional online accounts, transferring data or even launching denial of service attacks.
Comparison between session hijacking and session spoofing
Session spoofing and hijacking are similar in nature, but with an important difference.
Hijacking a session means the victim is already logged into a web application, and threat actors are essentially invading. Session spoofing refers to situations where cybercriminals try to masquerade as their victim and launch a new online session. This could happen long after the victim has logged off and is going about their day.
How Does Session Hijacking Work?
In order to see how web sessions get hijacked, you first need to understand what sessions are in the first place, and why they’re important.
Overview of the process of session hijacking
Entering your username and password to a web application starts an HTTP authentication process between you and the service.
Although it helps verify that your credentials are correct, this type of connection is considered “stateless” by the server running the application. Rather than having to log in again every time you move from one page to another (or when you go from placing an order to checking out), sessions keep the original authentication active until you finish what you’re doing and log out.
Hijackers are essentially stealing these sessions by interfering with the control mechanisms that enable them.
Common methods used by attackers
One of the most common approaches to session hijacking involves rogue actors monitoring their prospective victim’s network traffic.
This is sometimes known as “session sniffing,” and much like a dog that detects the scent of meat, cybercriminals may discover the victim has chosen to log into an application using an unsecured connection like public Wi-Fi hotspot. This opens the door for them to steal the session cookie, otherwise known as a session side-jacking attack.
Attacks can happen even more unexpectedly if cybercriminals can use a phishing scheme to dupe someone into clicking on an attachment or link that downloads a trojan onto their machine. Cybercriminals can then activate the malware when the victim logs onto a specific site or application. In these “man-in-the-browser” attacks (which are similar to man-in-the-middle attacks) cybercriminals can then make requests that appear legitimate to the server, such as modifying transactions or performing other transactions.
Session fixation attacks are similar, at least in the way they fool innocent users. Threat actors will create their own session by setting up a bogus login page that gets sent to the victim. Once they log in, the fake session ID provides cybercriminals the access they were looking for.
The most direct approach is probably cross-site scripting, whereby attackers inject scripts into web applications or servers that contain a known vulnerability. Once those are running, threat actors can find session keys within the victim’s web browser and make themselves at home.
Real-life examples of session hijacking attacks
In late 2022, popular messaging and collaboration platform Slack admitted session hijackers had managed to break into its private GitHub repositories and steal some of its code. This reflected the proprietary work of its developers to continuously improve its service. By stealing employee session tokens, threat actors were easily able to perform a data breach.
Meanwhile, reports surfaced in late 2023 of threat actors stealing data by restoring expired sessions on Google accounts. The attacks began through social engineering campaigns that led victims to deactivate tools to protect against malware, at which point cybercriminals were able to spot multiple login attempts.
Then there was the flaw in Citrix’s NetScaler ADC and NetScaler Gateway products that exposed users to session hijacking. Though the vendor issued a patch, researchers reported a steady stream of attacks using the so-called CitrixBleed vulnerability against retailers, manufacturers and health-care organizations.
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Consequences of Session Hijacking
These kinds of attacks happen so often and with such ease in some cases that organizations should consider the fallout they face when they become the next victim.
Impact on user privacy and security
When hackers break into a user’s web application session, they can gain data that can be used in myriad ways.
By taking a victim’s passwords, email address or other personal details, for example, they could commit identity theft by posing as that individual by logging into their financial institution or their employer’s database.
If they opt for the latter, cybercriminals could compromise the privacy of the employer’s staff or customers, stealing even more data or targeting additional victims.
Potential financial losses due to compromised sessions
Many web applications, such as those run by an e-commerce retailer, save payment information to make online shopping more convenient for their customers. If those sessions get hijacked, though, threat actors could use that information to make additional purchases.
Financial theft can also happen if hijackers gain access to bank accounts or an organization’s procurement systems, where they can transfer money to their own accounts.
Reputation damage for businesses and organizations
Any IT security incident has the potential to undo all the time and effort organizations put into building strong relationships with their customers and the general public.
A successful session hijacking attempt means that cybercriminals could potentially infect an organization with malware, launch distributed denial of services (DDoS) attacks or other threats.
That in turn could mean organizations will have to communicate what happened to all the relevant stakeholders – not just their customers but law enforcement officials and possibly the media.
Preventing Session Hijacking
Rather than become an IT security statistic, it’s best to be proactive in making sure the way employees use web applications keeps data safe, and cybercriminals at bay.
Best practices for securing sessions
At a bare minimum, using HTTPS throughout web sessions helps avoid hijacking because it offers both clients and servers a secure connection where data is encrypted. Similarly, secure cookies restrict how data such as session IDs are stored and submitted.
Some IT departments go a step further by validating session data every time employees use a web application to check for any anomalies or inconsistencies in network traffic. Companies can also require sessions to timeout after a specific period, such as when users are inactive for a while.
Implementing strong authentication and encryption measures
Session hijacking may pose an increased risk for organizations whose authentication processes are based on single sign-on (SSO), because rogue actors could use the same credentials across a host of platforms. Multi-factor authentication (MFA) may offer an additional layer of protection.
Organizations should also secure the way session data is stored, and even explore regenerating session IDs at critical transitions within an application, such as when a privilege level changes.
Regularly updating software and applying security patches
Whether they opt for active or passive hijacking, it becomes easier for cybercriminals to target sessions in web applications that are exposed to publicly known bugs.
Vendors typically take care to regularly issue patches for these vulnerabilities. The more often these are tracked and applied, the more you’ve reduced the risk – not just the risk of session hijacking, but a number of other cyber threats.
How LastPass Protects Against Session Hijacking
Beyond the regular best practices, LastPass offers tools that can avoid or mitigate the likelihood that rogue actors will take over your employee’s web application sessions.
Features and functionalities that enhance session security
By offering secure password storage, MFA, breach monitoring and secure password creation, LastPass ensures session hijackers are either stopped in their tracks or won’t get very far. Even if a session is breached, for example, LastPass allows customers to store passwords and other sensitive data in an encrypted vault.
LastPass even offers security for autofills like forms, which means threat actors won’t be able to fool employees with bogus login pages.
Benefits of using LastPass to mitigate session hijacking risks
It’s not only important to choose a cybersecurity partner with great products and services, but proven processes. LastPass works with third-party testing services, for example, conducts regular security audits and identifies and addresses potential vulnerabilities by participating in a bug bounty program.
No matter your organization’s size or the sector in which it operates, employees should be able to use web applications with confidence, focusing on the work they’re doing rather than worrying about whether system access and data has been compromised.
Take the next natural step: Start your LastPass trial today.
