Polyglot Files
A polyglot file is validly interpreted in cybersecurity as two or more formats. It achieves this by 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 to be harmless file types.
ThreatNG's Role in Combating Polyglot File Threats:
ThreatNG provides a robust defense against polyglot file threats through its comprehensive external attack surface management, digital risk protection, and security ratings capabilities.
Superior Discovery and Assessment:
Domain Intelligence: ThreatNG's Domain Intelligence module offers several features that are highly relevant to discovering potential polyglot file vulnerabilities:
Exposed API Discovery & Exposed Development Environment Discovery: By identifying exposed APIs and development environments, ThreatNG can pinpoint areas where improper file upload handling might exist, creating opportunities for polyglot file attacks.
Application Discovery: ThreatNG's ability to identify web applications that handle file uploads is crucial, as these applications are prime targets for attackers attempting to exploit polyglot files.
Known Vulnerabilities: ThreatNG cross-references discovered applications and technologies with its intelligence repositories, enabling it to detect known vulnerabilities related to file handling and parsing that polyglot files could exploit.
Exposed Public Code Repositories: ThreatNG's analysis of code repositories for "Access Credentials (API Keys: Stripe API key, Google OAuth Key…), Access Tokens (Facebook access token); Generic Credentials (Username and password in URI…); Cloud Credentials (AWS Access Key ID Value…); Security Credentials (Cryptographic Keys…); Other Secrets… Configuration Files… System Configuration… and Network Configuration" is vital. This analysis can reveal insecure coding practices related to file handling or insufficient input validation, significantly increasing the risk of polyglot file exploitation.
Search Engine Exploitation: ThreatNG's Search Engine Exploitation capabilities can help identify:
Susceptible Files & Susceptible Servers: ThreatNG can discover inadvertently exposed files or servers through search engine queries, which an attacker could use to upload or distribute polyglot files.
Cloud and SaaS Exposure: ThreatNG's assessment of cloud and SaaS environments is crucial because these platforms are often used for file storage and sharing.
Open Exposed Cloud Buckets: ThreatNG can identify misconfigured cloud storage buckets (AWS, Microsoft Azure, and Google Cloud Platform) that attackers could use to host or distribute polyglot files.
Collaboration and Content Management SaaS: ThreatNG's assessment of platforms like "Box, SharePoint," and others can uncover potential vulnerabilities in file handling or sharing mechanisms that could enable polyglot file attacks.
Mobile Application Discovery:
ThreatNG discovers mobile apps and analyzes them for "Access Credentials (Amazon AWS Access Key ID, APIs…), Security Credentials (PGP private key block, RSA Private Key…), and Platform Specific Identifiers (Admin Directories, Amazon AWS S3 Bucket…)." This capability can identify vulnerabilities in how mobile apps handle files, potentially opening avenues for polyglot file attacks.
Continuous Monitoring and Intelligence Repositories:
Dark Web Presence: ThreatNG's monitoring of dark web activity can provide early warnings of polyglot file attacks being planned, discussed, or shared among threat actors.
Compromised Credentials: ThreatNG's discovery of leaked credentials can alert organizations to the risk of attackers bypassing authentication to upload polyglot files to vulnerable systems.
Known Vulnerabilities: ThreatNG's intelligence repositories, including information on known vulnerabilities, enable it to identify and assess potential polyglot file attack vectors proactively.
Archived Web Pages: ThreatNG's examination of archived web pages can reveal previous instances of file upload vulnerabilities or polyglot file uploads that attackers might attempt to exploit.
Technology Stack: ThreatNG's identification of an organization's technologies allows it to prioritize assessments and monitoring for known vulnerabilities related to those technologies and their file-handling capabilities.
Complementary Solutions & Collaboration:
ThreatNG's intelligence and detection capabilities can be used to enhance the effectiveness of other security solutions:
ThreatNG + Endpoint Detection and Response (EDR): EDR solutions can detect suspicious file behavior on endpoints, providing a critical layer of defense against polyglot files that bypass network security. ThreatNG's intelligence on file types, vulnerabilities, and attack patterns can enrich EDR alerts, enabling faster and more accurate 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 type and vulnerability intelligence can enhance SEG's detection capabilities, improving its ability to identify and block malicious files.
ThreatNG + Network Traffic Analysis (NTA): NTA tools can monitor network traffic for suspicious file uploads or downloads, providing network-level visibility into potential polyglot file activity. ThreatNG can provide valuable context for suspicious file transfers, aiding in identifying potential threats and malicious activity.
Example Scenario:
ThreatNG discovers an exposed API endpoint within an organization's web application (identified through "Exposed API Discovery"). Further analysis reveals that this API handles file uploads but lacks proper validation for file types (identified through "Sensitive Code Exposure" by analyzing code related to the API). 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, combined with its detailed investigation modules, 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.
