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IMP4GT IMPersonation Attacks in 4G NeTworks David Rupprecht , - - PowerPoint PPT Presentation
IMP4GT IMPersonation Attacks in 4G NeTworks David Rupprecht , - - PowerPoint PPT Presentation
IMP4GT IMPersonation Attacks in 4G NeTworks David Rupprecht , Katharina Kohls, Thorsten Holz, and Christina Ppper 25.02.2020 NDSS Symposium, San Diego, USA Motivation: Internet Passes 2 LTE Security Aims Mutual Authentication Traffic
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Mutual Authentication Traffic Confidentiality Identity & Location Confidentiality
LTE Security Aims
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Security Features Authentication and Key Agreement Connection
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Missing Integrity Protection
Control Plane User Plane Encryption stream cipher Integrity Protection
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Malleable Encryption
Encryption Decryption
$10 $100
Stream Cipher
1 1 1 1 1 1 1 1
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Already Known: Redirection
Can it be worse? Yes, with IMP4GT
/ˈɪmpækt/
Rupprecht, D., Kohls, K., Holz, T., & Pöpper, C. “Breaking LTE on Layer Two”. In 2019 IEEE Symposium on Security and Privacy (SP)
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Impersonation in 4G Networks (IMP4GT)
Uplink Downlink
Impersonation of a user towards the network on the user-plane Impersonation of a network towards the user on the user-plane
Breaks mutual authentication in both directions.
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The Basic Principle
Encryption Oracle Decryption Oracle Impersonation Malleable Encryption Reflection
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Reflection: ICMP Ping
IP / ICMP (ping) / Data IP / ICMP (ping) / Data
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Uplink Encryption Oracle
IP / UDP / Payload IP / PING Request / Payload UE Relay IP / UDP / Payload Keystream Generation Target Server Network IP (target_ip) / TCP / new Payload IP / PING Reply / Payload IP (target_ip) / TCP / new Payload Encrypted on the Radio Layer Already Open.
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Uplink Enc + Downlink Dec = Full Impersonation
UE Relay Keystream Generation Target Server Network Decryption Server Uplink Encryption Downlink Decryption Uplink Encryption Downlink Decryption
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- Commercial network and phone
- Uplink impersonation
- Visit a website only accessible by a victim: pass.telekom.de
- Upload a 10KB file to a server
- Downlink impersonation
- TCP connection towards the phone
- No interaction of the user
- connectivitycheck.android.com
- Checks if you have an Internet connection
Experiments
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Consequences
Providers
- Over Billing
- Authorization
Law Enforcement
- Lawful Interception
- Lawful Disclosure
Process User
- Privacy
- Firewall / NAT
- IoT
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- Fully specified and deployed
- Unlikely…
- Optional integrity protection
- Limited support in early