CloudAV: N-Version Antivirus in the Network Cloud Jon Oberheide, Evan Cooke, Farnam Jahanian Electrical Engineering and Computer Science Department, University of Michigan USENIX Security /05/21 Presented by Seungbae Kim * Slides are borrowed from the author’s presentation file

Contents Motivation and Limitations of Antivirus AV as an In-Cloud Network Service Implementation Evaluation Conclusion CloudAV: N-Version Antivirus in the Network Cloud 1/19

Antivirus Widely deployed Last line of defense Over $10 billion market in 2008 Over 50% of security software revenue CloudAV: N-Version Antivirus in the Network Cloud 2/19

Antivirus Limitations Detection Coverage –Low detection rates –Slow response to emerging threats AV Software Vulnerabilities –Complexity leads to security risk –Inherently high privileges CloudAV: N-Version Antivirus in the Network Cloud 3/19

Detection Degradation CloudAV: N-Version Antivirus in the Network Cloud 4/19

Antivirus Limitations Detection Coverage –Low detection rates –Slow response to emerging threats AV Software Vulnerabilities –Complexity leads to security risk –Inherently high privileges CloudAV: N-Version Antivirus in the Network Cloud 5/19

CloudAV In-Cloud Detection –Moving the detection of malicious and unwanted files from end hosts into the network –Significantly lowers the complexity of host-based monitoring software N-Version Protection –Using a set of heterogeneous detection engines to provide analysis results on a file CloudAV: N-Version Antivirus in the Network Cloud 6/19

AV as an In-Cloud Network Service By providing antivirus as an in-cloud service: –Analyze files using multiple detection engines in parallel –Collect forensic data –Retrospectively detect previously infected hosts –Simplify host software –Centralize management and policy enforcement CloudAV: N-Version Antivirus in the Network Cloud 7/19

Architecture Lightweight host agent runs on desktops, laptops, and other devices Network service hosts the backend file analysis engines and fields requests from the host agent Archival and forensics service stores information on file analysis results CloudAV: N-Version Antivirus in the Network Cloud 8/19

Lightweight Host Agent Access to each file is trapped and diverted to a handling routine Generate a unique identifier for the file (eg. cryptographic hash) Compare UID to local and remote cache of previously analyzed files; send file to network service if not in either cache CloudAV: N-Version Antivirus in the Network Cloud 9/19

Network Service Receives incoming analysis requests from host agent File analyzed by collection of engines (N-version protection) Shared remote cache maintained in network service CloudAV: N-Version Antivirus in the Network Cloud 10/19

Network Service N-Version Protection –Multiple, independent implementations for the detection of malware –Independent vendors have heterogeneous detection routines, malware collection methodologies, and response times –Leverage heterogeneity to increase coverage CloudAV: N-Version Antivirus in the Network Cloud 11/19

Network Service Result Aggregation –The results from the different detections engines must be combined –To determine whether a file is safe to open, access, or execute Threat Report –The result of the aggregation process –Can contain a variety of metadata and analysis results about a file CloudAV: N-Version Antivirus in the Network Cloud 12/19

Archival and Forensics Service File access information –Sent by the host agent and stored securely by the network service The behavioral profiles of malicious software –Generated by the behavioral detection engines CloudAV: N-Version Antivirus in the Network Cloud 13/19

Retrospective Detection Detect previously unknown threats Network service with RD: –Host sends 0-day to network service, 0-day evades all detection engines, 0-day archived, host becomes infected –Vendor releases new signatures to address threat. Network service rescans archived files, detects threat! –Administrator notifies of infected hosts and quarantines them CloudAV: N-Version Antivirus in the Network Cloud 14/19

Implementation Host Agent –Platforms Windows 2000/XP/Vista, Linux 2.4/2.6, FreeBSD 6 –Simple and lightweight host agent Win32 host agent: ~1500 LOC Linux/BSD host agent: <300 LOC, Python Network Service –Backend analysis engines 10 antivirus engines: –Avast, AVG, BitDefender, ClamAV, F-Prot, F-Secure, Kaspersky, McAfee, Symantec, Trend Micro 2 behavioral engines –Norman Sandbox, CWSandbox CloudAV: N-Version Antivirus in the Network Cloud 15/19

Evaluation Malware Dataset –Obtained through Arbor Malware Library (AML) Distributed darknet honeypots, Spam traps, Honeyclient –7220 malware samples –Collected over a year period November 12 th, 2006 to November 11 th, 2007 CloudAV: N-Version Antivirus in the Network Cloud 16/19

N-Version Protection CloudAV: N-Version Antivirus in the Network Cloud 17/19

Retrospective Detection CloudAV: N-Version Antivirus in the Network Cloud 18/19

Conclusion Traditional host-based antivirus –Low detection rate –Slow response to emerging threats –Complexity leads to security risk CloudAV –In-cloud detection & N-version protection Simplify host software, Better detection, Retrospective detection, Centralized management CloudAV: N-Version Antivirus in the Network Cloud 19/19