New Method to Establish Covert Channel Communication by Abusing X.509 Digital Certificates

Security researchers from Fidelis identified a new method to establish a covert channel communication by abusing widely implemented X.509 public key certificates. Certificates remain as a critical component of secure connection to a website.

When a browser establishes a secure connection to a site, it checks that the server has the private key for the certificate it’s trying to use, this is no one can use our certificate.

A TLS X.509 certificate would have many fields Version, signature algorithm, Validity, subject and so on. Data transferred within X.509 extension can bypass the detection methods, attackers could take it as an advantage to hide data in any one of these fields.

Also Read Bypassing and Disabling SSL Pinning on Android to Perform Man-in-the-Middle Attack

The covert channel is not a new one, history reveals various publications, there are methods to exfiltrate data by using ICMP shell, yes PING as great convert channel to get victim shell access using ICMP Shell.

Jason from Fidelis describes a system that could be used to send or receive data from both a client and a server perspective utilizing research into X.509 certificates specifically in areas where you can place arbitrary binary data into the certificate or utilizing them as a covert channel. The research demonstrates that a sufficiently motivated attacker can utilize technologies outside of their intended purposes to not only accomplish their goals but also end up bypassing common security measures in the process.

Researchers published a PoC explaining the malicious binary could be transferred over TLS traffic that stimulates the malware that already installed in the system.

Abusing X.509 Digital CertificatesAbusing X.509 Digital Certificates

Mitigations

Researchers suggested mitigations and the detection are possible by creating YARA and Suricata rule by pivoting SSL handshake to detect unexpected extensions and large octet lengths.

Due to widespread of X.509 certificates, most of the organizations are open to attack, disabling the self-signed as like in the PoC could be an effective security measure.

Gurubaran

Gurubaran is a co-founder of Cyber Security News and GBHackers On Security. He has 10+ years of experience as a Security Consultant, Editor, and Analyst in cybersecurity, technology, and communications.

Recent Posts

Attackers Exploit Microsoft Entra Billing Roles to Escalate Privileges in Organizational Environments

A startling discovery by BeyondTrust researchers has unveiled a critical vulnerability in Microsoft Entra ID…

22 hours ago

Threat Actors Exploit Google Apps Script to Host Phishing Sites

The Cofense Phishing Defense Center has uncovered a highly strategic phishing campaign that leverages Google…

23 hours ago

Dadsec Hacker Group Uses Tycoon2FA Infrastructure to Steal Office365 Credentials

Cybersecurity researchers from Trustwave’s Threat Intelligence Team have uncovered a large-scale phishing campaign orchestrated by…

24 hours ago

Beware: Weaponized AI Tool Installers Infect Devices with Ransomware

Cisco Talos has uncovered a series of malicious threats masquerading as legitimate AI tool installers,…

1 day ago

Pure Crypter Uses Multiple Evasion Methods to Bypass Windows 11 24H2 Security Features

Pure Crypter, a well-known malware-as-a-service (MaaS) loader, has been recognized as a crucial tool for…

1 day ago

Attackers Exploit Microsoft Entra Billing Roles to Escalate Privileges

A recent discovery by security researchers at BeyondTrust has revealed a critical, yet by-design, security…

1 day ago