Cloudflare DDoS Protection Vulnerable to Logic Flaws: Cloudflare’s DDoS protection faces an unexpected vulnerability stemming from logic flaws, potentially leaving its users exposed to attacks. This loophole allows attackers to bypass the security measures of the internet giant by exploiting shared infrastructure.
In this news item, we delve into the specifics of this issue, its potential impact, and recommended defense strategies.
Key Takeaways on Cloudflare DDoS Protection Vulnerable to Logic Flaws:
- Bypassing Cloudflare Protections: Attackers can exploit logic flaws in Cloudflare’s security controls to evade its security measures, potentially harming Cloudflare customers.
- Low Barrier to Entry: The attack only requires hackers to create a free Cloudflare account, making it accessible to a wide range of threat actors.
- Mitigation Measures: Using custom certificates for “Authenticated Origin Pulls” and Cloudflare Aegis can help mitigate these vulnerabilities.
Cloudflare Vulnerabilities Exposed
Recent discoveries have revealed vulnerabilities in Cloudflare’s security infrastructure that could allow attackers to bypass its firewall and DDoS prevention mechanisms. These vulnerabilities have the potential to undermine the effectiveness of Cloudflare’s protection systems, putting its customers at risk.
Easy Entry for Attackers
One concerning aspect of these vulnerabilities is that attackers can take advantage of them with minimal effort. All that’s required is for hackers to create a free Cloudflare account, which is then used as part of the attack process.
However, it’s crucial to note that attackers must have knowledge of the targeted web server’s IP address to exploit these flaws.
Logic Flaws Uncovered
The vulnerabilities in question stem from Cloudflare’s strategy of using shared infrastructure that accepts connections from all tenants.
Specifically, two vulnerabilities were identified, affecting Cloudflare’s “Authenticated Origin Pulls” and “Allowlist Cloudflare IP Addresses.”
Authenticated Origin Pulls Vulnerability
“Authenticated Origin Pulls” is a security feature provided by Cloudflare to ensure that HTTP(s) requests sent to an origin server come exclusively through Cloudflare, preventing unauthorized access.
However, the vulnerability arises from Cloudflare’s use of a shared certificate for all customers, rather than tenant-specific certificates.
This oversight permits attackers to create custom domains, point them to victims’ IP addresses, and tunnel their attacks through Cloudflare, effectively bypassing protection features.
Allowlist Cloudflare IP Addresses Vulnerability
The second vulnerability impacts Cloudflare’s “Allowlist Cloudflare IP Addresses,” a security measure that restricts traffic to only those originating from Cloudflare’s IP address range.
Attackers can exploit a logic flaw by configuring a domain with Cloudflare, directing their domain’s DNS A record to the target victim’s server’s IP address.
By disabling protection features for the custom domain, attackers can route malicious traffic through Cloudflare, making it appear trusted from the victim’s perspective.
Mitigating These Vulnerabilities
To mitigate these vulnerabilities, it is recommended to take the following measures:
- Use Custom Certificates: Instead of relying on Cloudflare’s shared certificate for “Authenticated Origin Pulls,” opt for custom certificates.
- Leverage Cloudflare Aegis: If available, use Cloudflare Aegis to define a more specific egress IP address range dedicated to each client.
Reporting and Response
Researchers Florian Schweitzer and Stefan Proksch, who discovered these logic flaws, reported them to Cloudflare via HackerOne. However, the issue was closed as “informative.”
It remains to be seen if Cloudflare will implement additional protection mechanisms or notify clients with potentially risky configurations.
Conclusion
The vulnerabilities in Cloudflare’s security controls pose a significant risk to its customers. Addressing these issues by following recommended mitigation measures is crucial to ensure robust protection against potential attacks.
About Cloudflare:
Cloudflare is a prominent internet security and infrastructure company known for providing various services, including content delivery and DDoS protection.
