Posts Tagged ‘CybersecurityTools’
[DefCon32] Sshamble: Unexpected Exposures in the Secure Shell
The Secure Shell (SSH), a cornerstone of secure communication, powers a vast array of systems beyond traditional POSIX environments, from network devices to Windows file transfer tools. HD Moore and Rob King, security researchers at Rumble, Inc., delve into the lesser-known implementations of SSH, uncovering surprising vulnerabilities. Their presentation introduces “Sshamble,” an open-source tool designed to probe SSH services, revealing weaknesses in diverse implementations. With OpenSSH dominating 80% of deployments, HD and Rob explore the long tail of alternative servers, exposing flaws like null byte password acceptance in honeypots and key mismanagement.
Their journey, sparked by the XZ backdoor investigation, reveals tens of thousands of vulnerable SSH instances. By analyzing server behaviors and handshake anomalies, Sshamble empowers researchers to identify and exploit misconfigurations, urging a reevaluation of SSH’s assumed security.
The Landscape of SSH Implementations
HD outlines SSH’s evolution from a remote shell to a ubiquitous transport protocol, second only to TLS. While OpenSSH prevails, alternatives like Dropbear and niche libraries in devices and forges introduce variability. Their research uncovers servers accepting invalid credentials or mangled requests, often indicative of honeypots or flawed implementations. For instance, many honeypots accept null byte passwords, a trait absent in legitimate OpenSSH setups.
This diversity, while functional, creates an attack surface ripe for exploitation, as non-standard servers deviate from expected security models.
Sshamble: A Tool for Discovery
Rob introduces Sshamble, a versatile tool that scans SSH services across specified ports, performing handshakes to detect anomalies. It identifies honeypots by exploiting behaviors like accepting any public key or malformed passwords. The tool’s open-source release on GitHub encourages community contributions, enhancing its ability to catalog and test SSH implementations.
Demonstrations show Sshamble pinpointing vulnerable servers, including those misconfigured to accept arbitrary credentials, highlighting the need for rigorous server validation.
Exploiting SSH Weaknesses
HD details specific vulnerabilities, such as key generation issues in libraries and servers that bypass standard authentication. While client-side tools like PuTTY were not the focus, server-side flaws dominate, with some implementations ignoring protocol specifications. These gaps allow attackers to bypass authentication or inject malicious data, compromising systems.
The XZ backdoor, though not directly exploitable, inspired their broader exploration, revealing systemic issues in SSH ecosystems.
Mitigating SSH Risks
Rob emphasizes hardening SSH deployments through strict configuration and regular audits. Disabling null byte passwords, enforcing strong key management, and monitoring handshake behaviors mitigate risks. Sshamble aids defenders by identifying weak implementations, urging organizations to standardize on robust servers like OpenSSH.
The talk concludes with a call for ongoing research into SSH’s evolving attack surface, leveraging tools like Sshamble to bolster defenses.
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[DefCon32] 1 for All, All for WHAD: Wireless Shenanigans Made Easy
In the ever-evolving landscape of wireless security, the proliferation of bespoke tools for protocol attacks creates a fragmented ecosystem. Romain Cayre and Damien Cauquil, seasoned researchers from Quarkslab, introduce WHAD, a unifying framework designed to streamline wireless hacking. By offering a standardized host/device communication protocol, WHAD enhances interoperability across diverse hardware, liberating researchers from the constraints of proprietary firmware. Their presentation unveils a solution that fosters collaboration and innovation, making wireless exploits more accessible and sustainable.
Romain, maintainer of the Mirage tool for Bluetooth and beyond, and Damien, creator of BtleJack, share a passion for dissecting wireless protocols. Their work addresses a critical pain point: the reliance on specialized, often obsolete hardware for attacks on smartphones, peripherals, and vehicles. WHAD consolidates these efforts, supporting protocols like Bluetooth Low Energy (BLE), Zigbee, and Logitech Unifying, while enabling researchers to focus on exploits rather than hardware compatibility.
The framework’s extensible architecture allows seamless integration with devices like Nordic nRF boards, ensuring longevity as hardware evolves. By presenting WHAD’s capabilities through practical demonstrations, Romain and Damien showcase its potential to transform wireless security research.
The Problem with Wireless Tools
Wireless security tools, while effective, often tie researchers to specific hardware and custom protocols. Damien highlights the chaos of tools like BtleJack, Mirage, and GATTacker, each requiring unique firmware and communication methods. This fragmentation forces researchers to reinvent protocols, limiting scalability and accessibility.
WHAD addresses this by providing a unified protocol stack, abstracting hardware complexities. It supports multiple devices through a single interface, reducing the need for redundant development. For instance, a researcher targeting BLE can use WHAD with any compatible dongle, avoiding the need to craft bespoke firmware.
WHAD’s Architecture and Capabilities
Romain details WHAD’s modular design, comprising a host-side Python library and device-side firmware. The framework supports sniffing, injection, and interaction across protocols. Demonstrations include BLE relay attacks, where WHAD discovers services and manipulates devices like smart bulbs, altering colors or states.
Its flexibility extends to hardware CTFs, with WHAD emulating BLE challenges and LoRa gateways. Integration with tools like Scapy enhances packet manipulation, while firmware availability on GitHub encourages community contributions.
Real-World Applications and Impact
Damien shares WHAD’s internal use at Quarkslab, where it facilitated a BLE GATT fuzzer, uncovering CVEs in expressive controllers. Research into screaming channel attacks leveraged WHAD to instrument custom link-layer traffic, showcasing its versatility.
The framework’s open-source release, available via PyPI and GitHub, invites contributions for new protocols and hardware support. Romain emphasizes its role in democratizing wireless research, reducing barriers for newcomers and veterans alike.
Future Potential and Community Engagement
WHAD’s vision extends beyond current protocols, with plans to incorporate emerging standards. By fostering a collaborative ecosystem, Romain and Damien aim to unify disparate tools, ensuring resilience against hardware obsolescence.
Their call for contributors underscores the community-driven ethos, encouraging bug reports, documentation, and firmware development. WHAD’s potential lies in its adaptability, empowering researchers to explore new attack surfaces efficiently.