Polyglot Files
A polyglot file is validly interpreted in cybersecurity as two or more formats. It achieves this by cleverly combining multiple file types' structural elements and syntax so that each format's parser can process it without encountering errors.
Why they are a concern in cybersecurity:
Evasion of Security Measures: Polyglot files can bypass traditional security tools that rely on file extensions or simple content inspection. A file might appear harmless (e.g., an image or a text file) but contain hidden malicious code in a different format.
Delivery of Malware: Attackers use polyglot files to deliver malware undetected. They can embed malicious code within seemingly innocuous files, tricking users into opening them and executing the hidden payload.
Exploitation of Vulnerabilities: Polyglot files can exploit software vulnerabilities that handle multiple file formats. If the software doesn't correctly validate all the formats a polyglot file claims to be, it could be tricked into executing malicious code.
Examples of polyglot files:
Image/Script: A file that appears as a valid image but also contains executable JavaScript code.
Document/Executable: A file that can be opened as a document but contains a hidden executable program.
Archive/Script: A file that can be extracted as an archive but also contains malicious scripts that run when the archive is opened.
Defense against polyglot files:
Deep Content Inspection: Use security tools that perform deep content inspection and analyze the actual structure and content of files rather than just relying on file extensions.
Behavior-Based Detection: Employ security solutions that monitor file behavior after they are opened or executed, looking for suspicious actions that might indicate malicious activity.
User Education: Train users to be cautious about opening files from unknown or untrusted sources, even if they appear harmless file types.
ThreatNG's Role in Combating Polyglot File Threats:
Superior Discovery and Assessment:
Exposed API Discovery & Exposed Development Environment Discovery: These modules could uncover APIs or development environments, inadvertently exposing file upload functionalities susceptible to polyglot file attacks.
Application Discovery: ThreatNG can identify web applications that handle file uploads, making them potential targets for polyglot attacks.
Known Vulnerabilities: ThreatNG could cross-reference discovered applications and technologies with known vulnerabilities related to polyglot file handling.
Exposed Public Code Repositories: ThreatNG's analysis of code repositories might reveal insecure coding practices related to file handling or parsing, increasing the risk of polyglot file exploitation.
Susceptible Files & Susceptible Servers: Search engine queries might reveal inadvertently exposed files or servers vulnerable to polyglot file uploads.
Open Exposed Cloud Buckets: ThreatNG can identify misconfigured cloud storage buckets that could be leveraged to host or distribute polyglot files.
Collaboration and Content Management SaaS: ThreatNG's assessment of these platforms (SharePoint, Box, etc.) could identify potential vulnerabilities in their file handling or sharing mechanisms that might enable polyglot file attacks.
Continuous Monitoring and Intelligence Repositories:
Dark Web Presence: Monitoring dark web chatter could provide early warnings of polyglot file attacks being planned or shared among threat actors.
Compromised Credentials: ThreatNG discovered leaked credentials that could allow attackers to bypass authentication and upload polyglot files to vulnerable systems.
Known Vulnerabilities: Staying current with the latest information enables ThreatNG to identify and assess potential polyglot file attack vectors proactively.
Archived Web Pages: Examining archived web pages could reveal previous instances of polyglot file uploads or vulnerabilities that attackers might try to exploit again.
Technology Stack: Knowing an organization's technologies allows ThreatNG to prioritize assessments and monitoring for known vulnerabilities related to those technologies and their file-handling capabilities.
Complementary Solutions & Collaboration
ThreatNG + Endpoint Detection and Response (EDR): EDR solutions can detect suspicious file behavior at the endpoint, providing an additional layer of defense against polyglot files that manage to bypass network-level security. ThreatNG's intelligence could enrich EDR alerts, aiding in faster incident response.
ThreatNG + Secure Email Gateways (SEG): SEGs can scan email attachments for potential polyglot files, preventing them from reaching end-users. ThreatNG's file types and vulnerability intelligence could enhance the SEG's detection capabilities.
ThreatNG + Network Traffic Analysis (NTA): NTA tools can monitor network traffic for signs of polyglot file uploads or downloads. ThreatNG could provide context for suspicious file transfers, aiding in identifying potential threats.
Example Scenario
ThreatNG discovers an exposed API endpoint within an organization's web application. Further analysis reveals that this API handles file uploads but needs proper validation for file types. ThreatNG raises an alert, highlighting the potential for polyglot file attacks. Armed with this intelligence, the security team can promptly address the vulnerability by implementing stricter file validation or deploying a web application firewall (WAF) with advanced file type detection capabilities.
ThreatNG's extensive capabilities in external attack surface management, digital risk protection, and security ratings, coupled with its investigation modules, can significantly enhance an organization's ability to proactively identify, assess, and mitigate the risks of polyglot files. By continuously monitoring the external attack surface, correlating intelligence from various sources, and providing actionable insights, ThreatNG empowers security teams to stay ahead of emerging threats and protect their organizations from sophisticated attacks.
