Business operations

Prevent a replay attack from disrupting your business operations.

Replay attacks have nothing to do with rewinding a VHS tape!

Have you been curious about replay attacks? A replay attack occurs when a cyber attacker intercepts a message and delays it or replaces it with another message. It looks a lot like a ‘man in the middle’ (MiTM) offensive. However, in a replay attack, the interceptor does not need to decrypt the data packets.

Indeed, a replay attack is much easier to use than a MiTM attack. A cyber attacker also does not need a lot of technical knowledge to take advantage of it. Essentially, replay attacks are more accessible than MiTM attackstherefore they are more dangerous.

In this article, I’ll dive deeper into what replay attacks are and how you can protect yourself against them. Let’s start with a definition first!

What is a replay attack?

A replay attack is a network-based attack where a cyberattacker intercept traffic between network nodes and pipelines packet sniffing. Attackers often seek Session ID and Passwords end users accessing server-based services.

A replay attack requires access to the target network. Cybercriminals often conduct it as a physical attack on the site. That said, attackers can also use devices such as LAN turtles to relay data offsite. Cyber ​​attackers usually install these LAN turtles between the Network interface card and the rest of the network.

When onsite, a cyberattacker can often use a redirect attack or an ARP poisoning attack. This way they can route traffic to the attacker without adding additional hardware to the network.

Once the attacker gains access to a target user’s account traffic messages and server, for example, packets are sniffed and redirected to destination. Once a cyberattacker receives something valuable, like a user’s username and password, they can use that information even if the user is offline.

The goal of a replay attack is similar to a MiTM attack: for steal user information or credentials. After that, attackers can access major trading platforms for further exploitation. The difference is that MiTM attacks use Wi-Fi interception to help steal network credentials. Additionally, MiTM packet sniffing mostly occurs from outside the network.

On the other hand, replay attacks usually occur from the network to help increase privileges. They also provide access to segmented areas of the business. You can use traffic encryption protocols with router-based VPNs to ensure that even packets from mobile devices are safe from packet sniffing.

Now that you know what replay attacks are, let’s see how they can be used against you!

How can a replay attack affect a business?

Replay Attacks often help a criminal gain access to segmented parts of your business and increase permissions. To do this, the attacker targets staff with elevated privileges and little experience in cybersecurity. Examples include CEOs or board members who had access to the system as the company grew. This also includes low-level or new business unit managers, project champions, and IT administrators. Cyber ​​attackers can also use replay attacks to access server-based platforms or most on-premises front-end platforms.

Once an attacker has all the credentials they need, they can implement malware and perform other malicious actions. These include:

  • Implementation of ransomware through the network
  • Access intellectual property sell to others
  • Destroy or create fake users; they do this to send details of “new” employees to HR for processing onsite facility access cards

Now let’s see how you can prevent replay attacks!

How you can prevent replay attacks

To prevent replay attacks from happening, there are a few things you can do. First, implement Secure socket layer (SSL) Where Transport Layer Security (TLS) for all communications with a HTTPS policy everywhere. This will then encrypt your communication, which can reduce the ability of attackers to detect information.

You can also hash of salt with a Session ID and timestamp. This way the attacker can no longer use the hashes, as they are only valid for a certain session ID or timestamp. Also, the attacker will not reuse intercepted packets.

Additionally, make sure user cookies are deleted periodically from browsers. Cookies often contain session identifiers. And attackers can use these credentials to impersonate you. Also, an attacker can watch what you are doing on the internet.

Another thing to consider is to make sure you prevent end users from customizing their browser. In fact, personalization provides attackers with ways to identify users, habits, and future attack vectors. Going a step further, some companies try to keep identical end-user hardware for this reason too. Management may want use lightweight laptops with screen sizes, resolutions, firmware, and hardware configurations that can also set them apart.

Now you know everything you need to keep your business safe! Let’s conclude.

Final Thoughts

You can stop replay attacks using basic security measures as part of your operations security (OPSEC) and infrastructure hardening processes. When these measures are in place, an attack on your network will become less likely.

You should use HTTPS to encrypt all the traffic. If possible, consider using routers with VPNs to help encrypt traffic automatically sent from mobile devices. This prevents user error or automatic updates from sending unencrypted traffic over the network. If you combine HTTPS and password salting with a timestamp and session ID, you can effectively stop a replay attack.

Do you have any other questions about replay attacks? Check FAQs and Resources headings below!


What is a replay attack?

Replay Attacks occur when a message is intercepted by a cyberattacker on a network, which delays it or replaces it with another message. They do this to steal credentials and gain access server-side platforms by monitoring an end user’s traffic. This attack doesn’t need a lot of skill to implement because it doesn’t necessarily need to be decoded; the messages are repeated to access the platforms.

How can I prevent replay attacks?

Follow a SSL/TPS/HTTPS policy everywhere. You reduce the likelihood of cyberattackers reusing messages to gain access to server-side platforms. Salt hashes with timestamps and session IDs can also help. Also make sure that users cannot customize their browsers, as this can easily identify them as targets. One last thing you can do is clear your browser cookies from time to time.

Is a VPN good enough to prevent a replay attack?

No, you should consider implement timestamps and session ids with HTTPS everywhere. If you use VPNs, use one that has endpoint protection to reduce the risk of replay attacks intercepting VPN server communications. Also, make sure your users clear browser cookies often.

How do attackers use replay attacks against me?

Replay attacks often help criminals steal credentials users. Then cybercriminals can carry out attacks that require enhanced permissions or access to certain platforms such as ERP systems. One use could be to help spread ransomware at strategic business locations. To mitigate replay attacks, consider using HTTPS, SSL/TPS, and salted hashes with timestamps and session IDs.

Will using timestamps help prevent a replay attack?

Traffic timestamps stop cybercriminals to replay credentials. Once the traffic is exhausted, it can no longer be resent and accepted. You should also encrypt your traffic using SSL or GST and implement a HTTPS policy everywhere. Finally, use a router that supports automatic VPN connections to avoid accidentally sending unencrypted data, especially during automatic updates.


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