DNS Rebinding

DNS Rebinding

So you're browsing the web, visiting different stores. Normally, each store has its own security guard to make sure everything runs smoothly. But what if a clever thief could trick you into entering a different store disguised as the one you wanted? This is kind of what happens with DNS rebinding.

It's a sneaky technique some malicious websites use to bypass security measures on your computer and potentially reach other devices on your network. Let's explore what DNS rebinding is and how it works.

What is DNS Rebinding?

DNS rebinding is a cyber attack that tricks your browser into breaching the Same-Origin Policy (SOP), a fundamental security measure in SOP networking. The attack rebinds a domain name to a malicious IP address, allowing hackers to access your private network. 

Essentially, DNS rebinding turns your browser into a bridge for attackers, compromising your network security without your knowledge. To counter this threat, you must enable DNS rebind protection. This simple step can prevent unauthorized access and keep your data safe.

How DNS Rebinding Works

DNS rebinding is a sophisticated attack that plays on the way your browser and DNS servers interact. Here’s a simplified breakdown of how it works:

  1. Initial Request: You visit a seemingly harmless website controlled by an attacker. Your browser sends a DNS request to resolve the website's domain name into an IP address.
  2. Malicious Response: The attacker's DNS server responds with the IP address of their malicious server. At this point, everything appears normal to your browser.
  3. Changing the IP Address: After the initial request, the attacker quickly changes the DNS response for the same domain name to point to an IP address within your private network. This is the key step where the domain name gets "rebound" to a new IP address.
  4. Exploiting SOP: The Same-Origin Policy (SOP) usually prevents scripts on one origin (website) from accessing data on another origin. However, with DNS rebinding, the attacker's script running on your browser can now access devices and services on your local network because the browser still thinks it’s communicating with the original domain.
  5. Data Access and Exfiltration: Once the attacker has access to your internal network, they can exploit vulnerabilities in local devices or services to extract sensitive information, control devices, or launch further attacks.

Impact of DNS Rebinding

DNS rebinding attacks can have serious repercussions for both individuals and organizations. Here’s a closer look at the potential impacts:

1. Unauthorized Access

DNS query rebinding can grant attackers unauthorized access to your internal network. 

Once inside, they can explore and exploit any connected devices, such as printers, security cameras, and smart home gadgets. This access can lead to further attacks or data theft.

2. Data Theft

One of the primary goals of DNS rebinding is to steal sensitive information. Attackers can siphon off personal data, financial details, and confidential business information. 

This data can be used for identity theft, financial fraud, or sold on the dark web.

3. Device Compromise

By gaining access to your internal network, attackers can install malware or ransomware on your devices. 

This can lead to device malfunction, loss of data, or being locked out of your own systems until a ransom is paid.

4. Network Disruption

Attackers can use DNS rebinding to disrupt your network operations. 

They might change settings on network devices, causing connectivity issues, slowing down network performance, or even making certain services unavailable.

5. Security Breach Costs

For organizations, the financial impact of a DNS rebinding attack can be substantial. Costs can include data breach fines, legal fees, and the expense of restoring and securing compromised systems. 

Additionally, there might be long-term damage to the organization’s reputation and loss of customer trust.

6. Compliance Violations

Many industries have strict data protection regulations. A DNS rebinding attack resulting in data loss or unauthorized access can lead to compliance violations. 

This can incur hefty fines and additional scrutiny from regulatory bodies.


In essence, DNS rebinding is a subtle yet dangerous technique that exploits the trust your browser places in domain name resolutions. By manipulating DNS responses, attackers can bypass security measures and gain unauthorized access to your internal network. This can lead to unauthorized access, data theft, device compromise, network disruption, significant financial costs, and compliance violations.

Published on:
June 18, 2024
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