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Is TLS Your Biggest Problem? The Appendix

16 Dec 2024 - nickpending

This technical analysis serves as a companion piece to our main article “Is TLS Your Biggest Problem?” While the main article examines the broader implications of TLS protocol security, these appendices provide exhaustive technical details across four critical areas: network position prerequisites, browser/library implementation timelines, network position analysis, and comprehensive CVE analysis.

For security practitioners and technical teams, these appendices offer the detailed technical foundation underlying the main article’s conclusions. By examining the specific technical requirements, historical implementation details, and practical attack considerations, we demonstrate why theoretical vulnerabilities often face significant practical exploitation barriers.

Appendix A: Network Position Prerequisites

  1. Passive Observation Capabilities
    • Network tap installation
      • Physical access requirements
      • Span port configuration
      • Traffic mirroring setup
      • Data capture methodology
    • Infrastructure compromise points
      • Routers and switches
      • Firewalls and security devices
      • Virtual infrastructure
      • Cloud provider systems
    • Traffic routing requirements
      • BGP manipulation
      • DNS poisoning
      • ARP spoofing
      • Route injection
  2. Active Manipulation Requirements
    • Protocol downgrade mechanics
      • TLS version negotiation interference
      • Cipher suite manipulation
      • Handshake modification
      • Alert message handling
    • Certificate operations
      • Certificate chain validation
      • Trust store manipulation
      • Warning bypass methods
      • Pinning circumvention
    • Traffic modification techniques
      • Packet injection
      • Session hijacking
      • Connection reset
      • Data alteration

Appendix B: Browser/Library Support Timeline

Browser Security Evolution

  1. Chrome
    • SSL Protocol Support
      • SSL 3.0 disabled: v40 (January 2015)
      • TLS 1.0 mitigations: v16 (2011)
      • TLS 1.1 enabled: v22 (2012)
      • TLS 1.2 default: v29 (2013)
    • Cipher Suite Changes
      • 3DES deprecation: August 2016
      • Export ciphers removed: March 2015
      • RC4 removal: February 2015
      • AEAD preference: September 2013
    • Security Features
      • HSTS preload list: 2011
      • Certificate pinning: 2011
      • Mixed content blocking: 2013
      • Automatic upgrades: 2014
  2. Firefox
    • SSL Protocol Support
      • SSL 3.0 disabled: v34 (December 2014)
      • TLS 1.0 mitigations: v10 (2012)
      • TLS 1.1 enabled: v23 (2013)
      • TLS 1.2 default: v27 (2014)
    • Cipher Suite Changes
      • 3DES deprecation: September 2016
      • Export ciphers removed: April 2015
      • RC4 removal: January 2015
      • AEAD preference: April 2014
    • Security Features
      • HSTS support: 2010
      • Certificate pinning: 2011
      • Mixed content blocking: 2013
      • Automatic upgrades: 2015
  3. Internet Explorer/Edge
    • SSL Protocol Support
      • SSL 3.0 disabled: December 2014
      • TLS 1.0 mitigations: IE 11 (2013)
      • TLS 1.1 enabled: IE 11 (2013)
      • TLS 1.2 default: IE 11 (2013)
    • Cipher Suite Changes
      • 3DES deprecation: October 2016
      • Export ciphers removed: May 2015
      • RC4 removal: April 2015
      • AEAD preference: June 2014
    • Security Features
      • HSTS support: IE 11 (2013)
      • Certificate pinning: IE 11 (2013)
      • Mixed content blocking: IE 9 (2011)
      • Automatic upgrades: Edge (2015)

Library Implementation Timeline

  1. OpenSSL
    • Protocol Support
      • 1/(n-1) split: September 2011
      • Lucky 13 mitigations: February 2013
      • TLS compression disabled: May 2012
      • Export ciphers disabled: March 2015
    • Security Features
      • AEAD ciphers: December 2012
      • Timing attack protections: 2013
      • Extended master secret: June 2015
      • Session hash: March 2015
    • Version History
      • 1.0.1: March 2012 (TLS 1.1/1.2)
      • 1.0.2: January 2015 (Suite B)
      • 1.1.0: August 2016 (New architecture)
      • 1.1.1: September 2018 (TLS 1.3)
  2. GnuTLS
    • Protocol Support
      • 1/(n-1) split: January 2012
      • Lucky 13 mitigations: March 2013
      • TLS compression disabled: June 2012
      • Export ciphers disabled: April 2015
    • Security Features
      • AEAD ciphers: March 2013
      • Timing attack protections: 2013
      • Extended master secret: July 2015
      • Session hash: May 2015
  3. NSS
    • Protocol Support
      • 1/(n-1) split: October 2011
      • Lucky 13 mitigations: February 2013
      • TLS compression disabled: May 2012
      • Export ciphers disabled: March 2015
    • Security Features
      • AEAD ciphers: November 2012
      • Timing attack protections: 2013
      • Extended master secret: May 2015
      • Session hash: April 2015

Appendix C: Network Position Analysis

Attack Vectors by Network Position

  1. Physical Access
    • Direct Infrastructure Access
      • Console port connection
      • Physical interface manipulation
      • Hardware key extraction
      • Storage media access
    • Cable Manipulation
      • Fiber optic splitting
      • Copper wire tapping
      • Physical bypass installation
      • Hardware implants
    • Device Replacement
      • Network equipment substitution
      • Endpoint device replacement
      • Infrastructure modification
      • Hardware trojan insertion
  2. Local Network
    • ARP Attacks
      • ARP cache poisoning
      • Gratuitous ARP injection
      • ARP spoofing tools
      • MAC flooding
    • DHCP Attacks
      • DHCP starvation
      • Rogue DHCP servers
      • Option injection
      • Lease manipulation
    • Switch Attacks
      • CAM table overflow
      • SPAN port abuse
      • VLAN hopping
      • STP manipulation
    • WiFi Attacks
      • Evil twin deployment
      • Deauthentication
      • KARMA attacks
      • Client impersonation
  3. Remote Position
    • DNS Attacks
      • Cache poisoning
      • Response forgery
      • Subdomain injection
      • Record manipulation
    • Routing Attacks
      • BGP hijacking
      • Route injection
      • Path manipulation
      • AS path prepending
    • Infrastructure Attacks
      • Cloud provider compromise
      • CDN manipulation
      • Load balancer abuse
      • Proxy chain exploitation

Detection and Prevention Mechanisms

  1. Network Monitoring
    • Traffic Analysis
      • Protocol validation
      • Anomaly detection
      • Behavioral analysis
      • Pattern matching
    • Position Detection
      • ARP monitoring
      • Route validation
      • DNS verification
      • Certificate tracking
    • Attack Recognition
      • Signature matching
      • Heuristic analysis
      • Machine learning
      • Correlation engines
  2. Architectural Controls
    • Network Segmentation
      • VLAN implementation
      • Network isolation
      • Access control
      • Trust boundaries
    • Traffic Protection
      • VPN deployment
      • Encryption requirements
      • Protocol enforcement
      • Certificate pinning
    • Infrastructure Security
      • Hardware security
      • Physical access control
      • Configuration management
      • Change control

Appendix D: Comprehensive CVE Analysis

Cross-Version Vulnerabilities

  1. FREAK (CVE-2015-0204)
    • CVSS Score: 4.3 (Medium) (AV:N/AC:M/Au:N/C:N/I:P/A:N)
    • EPSS Score: 0.973 (97.3% predicted exploitation likelihood)
    • Affected versions: SSL 3.0, TLS 1.0, TLS 1.1
    • Attack Requirements:
      • Network Position: Active Manipulation
      • Protocol Requirements:
        • Server supports export-grade RSA (512-bit key)
        • Client accepts RSA_EXPORT cipher suites
        • Export ciphers present in cipher suite list
      • Implementation Requirements:
        • Vulnerable client-side RSA implementation
        • Server configured to accept export ciphers
        • Client maintains session after cipher renegotiation
      • Attacker Capabilities:
        • Traffic Manipulation: Ability to modify ClientHello message
        • Computational Resources: Computing power for 512-bit RSA factorization (~100 USD on AWS)
        • Time Constraints: Must complete factorization before session expiration
    • Mitigations:
      • Client-side:
        • Chrome 41 (March 2015): Export ciphers removed
        • Firefox 37 (April 2015): Export ciphers removed
        • IE/Edge (May 2015): Export ciphers removed
      • Library-side:
        • OpenSSL 1.0.2a (March 2015): Export ciphers disabled
        • NSS 3.19 (April 2015): Export ciphers removed
        • GnuTLS 3.4.0 (April 2015): Export ciphers disabled
    • Current status: Effectively mitigated through removal of export ciphers
  2. POODLE (CVE-2014-3566)
    • CVSS Score: 4.3 (Medium) (AV:N/AC:M/Au:N/C:P/I:N/A:N)
    • EPSS Score: 0.971 (97.1% predicted exploitation likelihood)
    • Affected versions: SSL 3.0, TLS variants affect CBC padding
    • Attack Requirements:
      • Network Position: Active Manipulation
      • Protocol Requirements:
        • SSL 3.0 support enabled
        • CBC mode ciphers in use
        • No TLS_FALLBACK_SCSV support
        • Client accepts SSL 3.0 connections
      • Implementation Requirements:
        • Vulnerable CBC padding implementation
        • Lack of version fallback protection
        • Client allows protocol version renegotiation
      • Attacker Capabilities:
        • Traffic Manipulation:
          • Ability to trigger TLS 1.0+ connection failures
          • Ability to modify ServerHello message or inject TCP RST packets
        • Request Control: Ability to force reconnection attempts
        • Time Constraints: Must complete attack before session timeout
    • Mitigations:
      • Client-side:
        • Chrome v40 (Jan 2015): SSL 3.0 disabled
        • Firefox v34 (Dec 2014): SSL 3.0 disabled
        • IE/Edge (Dec 2014): SSL 3.0 disabled
      • Library-side:
        • OpenSSL 1.0.1j (Oct 2014): SSL 3.0 disabled by default
        • NSS 3.17.4 (Dec 2014): SSL 3.0 disabled by default
        • GnuTLS 3.3.11 (Jan 2015): SSL 3.0 disabled by default
        • wolfSSL 3.4.0 (Dec 2014): SSL 3.0 disabled by default
    • Current status: Effectively mitigated in all modern browsers/libraries

TLS 1.0 Vulnerabilities

  1. BEAST (CVE-2011-3389)
    • CVSS Score: 4.3 (Medium) (AV:N/AC:M/Au:N/C:P/I:N/A:N)
    • EPSS Score: 0.975 (97.5% predicted exploitation likelihood)
    • Attack Requirements:
      • Network Position: Active Manipulation
      • Protocol Requirements:
        • TLS 1.0 or earlier with CBC mode ciphers
        • Predictable IV (inherited from previous ciphertext block)
        • No 1/(n-1) record splitting mitigation
      • Implementation Requirements:
        • Long-lived HTTPS session
        • Vulnerable client implementation without 1/(n-1) split
        • Application allows attacker-controlled data in requests
      • Attacker Capabilities:
        • Traffic Manipulation: Ability to inject controlled plaintext into encrypted requests
        • Timing Precision: Ability to synchronize requests with block boundaries
        • Traffic Analysis: Ability to identify and track encrypted blocks
        • Must process multiple requests to recover each byte
    • Mitigations:
      • Client-side:
        • Chrome: Fixed in v16 (2011) with 1/(n-1) split
        • Firefox: Fixed in v10 (2012) with 1/(n-1) split
        • IE: Fixed in v11 (2013) with 1/(n-1) split
      • Library-side:
        • OpenSSL 1.0.0e (2011): 1/(n-1) split implemented
        • GnuTLS 3.0.0 (2012): 1/(n-1) split implemented
        • NSS 3.12.11 (2011): 1/(n-1) split implemented
        • wolfSSL 2.3.0 (2012): 1/(n-1) split implemented
      • Protocol-side:
        • TLS 1.1: Explicit IV addresses the vulnerability
        • Preference for AEAD ciphers (AES-GCM)
    • Current status: Mitigated in all modern browsers/libraries for over a decade
  2. Sweet32 (CVE-2016-2183)
    • CVSS Score: 5.9 (Medium) (AV:N/AC:H/Au:N/C:P/I:N/A:N)
    • EPSS Score: 0.971 (97.1% predicted exploitation likelihood)
    • Attack Requirements:
      • Network Position: Active Manipulation
      • Protocol Requirements:
        • 3DES cipher suite in use (64-bit block size)
        • Long-lived HTTPS session (>8 hours typical)
        • High-bandwidth connection (>500 Mbps)
      • Implementation Requirements:
        • Client maintains single key for extended period
        • No maximum byte limit for single key usage
        • Server accepts 3DES cipher suites
      • Attacker Capabilities:
        • Traffic Manipulation: Ability to inject chosen plaintext into encrypted stream
        • Storage: ~32GB of same-key encrypted data
        • Processing: Birthday attack calculations
        • Must maintain session alive for extended period
    • Mitigations:
      • Client-side:
        • Chrome 53 (2016): 3DES deprioritized
        • Firefox 49 (2016): 3DES deprioritized
        • Edge 14 (2016): 3DES deprioritized
      • Library-side:
        • OpenSSL 1.1.0 (2016): 3DES deprioritized
        • NSS 3.26 (2016): 3DES deprioritized
        • GnuTLS 3.5.5 (2016): 3DES deprioritized
      • Protocol-side:
        • Preference for AES-GCM and ChaCha20-Poly1305
        • Maximum byte limits for single key usage
    • Current status: Limited impact due to cipher preferences and key usage limits
  3. CRIME (CVE-2012-4929)
    • CVSS Score: 4.3 (Medium) (AV:N/AC:M/Au:N/C:P/I:N/A:N)
    • EPSS Score: 0.969 (96.9% predicted exploitation likelihood)
    • Attack Requirements:
      • Network Position: Active Manipulation
      • Protocol

        TLS 1.1 Vulnerabilities

  4. BREACH (CVE-2013-3587)
    • CVSS Score: 4.3 (Medium) (AV:N/AC:M/Au:N/C:P/I:N/A:N)
    • EPSS Score: 0.968 (96.8% predicted exploitation likelihood)
    • Attack Requirements:
      • Network Position: Active Manipulation
      • Protocol Requirements:
        • HTTP compression enabled (gzip/DEFLATE)
        • HTTPS/TLS encryption
        • Reflected input in responses
      • Implementation Requirements:
        • Server enables HTTP compression
        • Application reflects user input
        • No response padding or timing randomization
      • Attacker Capabilities:
        • Traffic Manipulation: Ability to force victim to make repeated requests
        • Traffic Analysis: Measure encrypted response sizes accurately
        • Statistical Analysis: Process multiple samples for reliable results
    • Mitigations:
      • Application-level:
        • Disable HTTP compression
        • Length hiding (random padding)
        • Rate limiting
        • Secret rotation
        • Cross-site request forgery (CSRF) protection
      • Library-side:
        • Apache 2.4.4+ (2013): Compression disabled by default
        • Nginx 1.5.0+ (2013): Configurable compression exclusions
        • IIS 8.0+ (2013): Compression security features
    • Current status: Mitigated through configuration changes and application-level protections
  5. TIME (CVE-2013-1747)
    • CVSS Score: 4.3 (Medium) (AV:N/AC:M/Au:N/C:P/I:N/A:N)
    • EPSS Score: 0.967 (96.7% predicted exploitation likelihood)
    • Attack Requirements:
      • Network Position: Passive Observation
      • Protocol Requirements:
        • Compressed HTTPS responses
        • Consistent network conditions
        • No response timing randomization
      • Implementation Requirements:
        • Server-side compression enabled
        • Predictable processing timing
        • No artificial delays or padding
      • Attacker Capabilities:
        • High-precision timing measurements of responses
        • Statistical analysis of timing patterns
        • Ability to filter network jitter
        • Must process multiple samples for accuracy
    • Mitigations:
      • Server-side:
        • Disabled compression
        • Random padding addition
        • Response timing randomization
      • Library-side:
        • Apache 2.4.4+ (2013): Timing protection features
        • Nginx 1.4.0+ (2013): Configurable timing protections
        • IIS 8.0+ (2013): Enhanced security features
    • Current status: Limited practical impact due to deployed mitigations
  6. Lucky 13 (CVE-2013-0169)
    • CVSS Score: 4.3 (Medium) (AV:N/AC:M/Au:N/C:P/I:N/A:N)
    • EPSS Score: 0.972 (97.2% predicted exploitation likelihood)
    • Attack Requirements:
      • Network Position: Active Manipulation
      • Protocol Requirements:
        • CBC mode ciphers in use
        • MAC-then-Encrypt construction
        • Predictable padding processing
      • Implementation Requirements:
        • Non-constant time MAC processing
        • Vulnerable TLS implementation
        • No timing protection measures
      • Attacker Capabilities:
        • Traffic Manipulation: Generate specially crafted ciphertext
        • Timing Precision: Microsecond-level measurements
        • Statistical Analysis: Process timing variations
    • Mitigations:
      • Library-side:
        • OpenSSL 1.0.1d (2013): Constant-time MAC processing
        • GnuTLS 3.1.6 (2013): Constant-time MAC processing
        • NSS 3.14.3 (2013): Constant-time MAC processing
        • wolfSSL 2.5.0 (2013): Constant-time MAC processing
      • Protocol-side:
        • Preference for AEAD ciphers (AES-GCM)
        • Additional timing protections
    • Current status: Effectively mitigated in modern implementations through constant-time processing