360 likes | 488 Views
Using a Novel Blending Method Over Multiple Network Connections for Secure Communications. Jaime C. Acosta and John Medrano U.S. Army Research Laboratory. Motivation. Network attack steps Locate a network Analyze traffic Identify target Scan nodes for vulnerabilities Execute exploit
E N D
Using a Novel Blending Method Over Multiple Network Connections for Secure Communications Jaime C. Acosta and John Medrano U.S. Army Research Laboratory
Motivation • Network attack steps • Locate a network • Analyze traffic • Identify target • Scan nodes for vulnerabilities • Execute exploit • Issue • Node addresses and traffic flows
Motivation • Covert Communication • Traditionally seen as adversarial • Data exfiltration • From a defensive perspective • Hide data in decoy traffic • Hide node endpoints • Avoid scanning • Avoid suspicion for critical data
Covert Communication • Timing channels • Timing anomalies • Generally low throughput • Data channels • Unused fields, invalid messages • Once documented identification is trivial
Objectives • Scalable throughput • Reliable • Dynamic insertion point selection
Research Question Can we leverage characteristics of network flows for covert, secure communication?
Envisioned Approach B C A F D E
Envisioned Approach Conn1 Conn3 B C A Conn4 Conn2 Conn5 Conn7 F D E Conn8 Conn6 Connections: 1. Unidirectional 2. Fixed size messages sharing the same a. source and destination MAC, IP, and ports b. protocol type 3. Have an update rate 4. Have a complexity measure
Envisioned Approach Covert Communicators Conn1 Conn3 B C A Conn4 Conn2 Promiscuous Traffic Conn5 Conn7 F D E Conn8 Conn6
Envisioned Approach Hide data within high-complexity payloads Covert Communicators Conn1 Conn3 B C A Conn4 Conn2 Promiscuous Traffic Conn5 Conn7 F D E Conn8 Conn6
Methodology • Implement a system • Parameters for determining insertion points • Evaluate • Vary parameter values • Measure throughput and reliability
Network Blending Communication System (NBCS) Configuration Network Communications Subsystem Analysis Subsystem Display Subsystem
NBCS Analysis Subsystem Network Connection 1 Packets during window Connection 2 Connection 3
NBCS Analysis Subsystem Network Connection 1 Packets during window Connection 2 Connection 3
NBCS Analysis Subsystem Min/Max = byteComplexities
NBCS Analysis Subsystem Network Connection 1 Packets during window Freq. Distribution sum C Connection 1 complexity byteComplexities Connection 2 Connection 3
NBCS system Configuration Network Communications Subsystem Analysis Subsystem Display Subsystem
Communications Subsystem … … Covert data queue Connection 1 with sufficient complexity Latest packets with sufficient byteComplexities Connection 4 with sufficient complexity
Communications Subsystem … … Covert data queue Connection 1 with sufficient complexity Latest packets with sufficient byteComplexities • check • rateToUse Connection 4 with sufficient complexity Attach Sync and Checksum Bytes
Communications Subsystem … … Covert data queue Connection 1 with sufficient complexity Latest packets with sufficient byteComplexities Connection 4 with sufficient complexity
NBCS System Configuration Network Communications Subsystem Analysis Subsystem Display Subsystem
Requirements – How it can be done • Hub • Promiscuous by default • Switch • Port mirroring • Wireless • Within distance • Multicast • Within group
Requirements – How it can be done • Hub • Promiscuous by default • Switch • Port mirroring • Wireless • Within distance • Multicast • Within group
Evaluation • Controlled (favoring low detectability) • Window Size = 1000ms • Sync Bytes = 2 • Checksum Bytes = 2 • Protocol to Use = UDP • Rate Threshold = 10 • Rate to Use = 0.1
Evaluation • Independent • Byte Complexity Threshold [0.1-0.9] • Dependent • Throughput • Packet loss • Procedure • Covert sender and receiver start simultaneously • Covert data buffer is always full • Run for 5 minutes
Future Work • More beneficial to hide covert data based on byte similarity? • Wireless and multicast traffic? • Automatic parameter tuning in real time depending on network characteristics?
NBCS Analysis Subsystem Network Connection 1 Packets during window Connection 2 Connection 3
NBCS Analysis Subsystem Sample byte complexities
NBCS Analysis Subsystem Network Connection 1 Packets during window Min Max sum C Connection 1 complexity byteComplexities Connection 2 Connection 3