CVE-2020-26144: Samsung Galaxy I9305 RCE Vulnerability

CVE-2020-26144 Overview

CVE-2020-26144 is a Wi-Fi protocol vulnerability affecting WEP, WPA, WPA2, and WPA3 implementations across multiple device manufacturers. The vulnerability allows attackers to inject arbitrary network packets by exploiting improper validation of plaintext A-MSDU (Aggregated MAC Service Data Unit) frames. When the first 8 bytes of a frame correspond to a valid RFC1042 LLC/SNAP header for EAPOL, affected devices will accept plaintext A-MSDU frames regardless of network encryption configuration.

This vulnerability is part of the broader FragAttacks (Fragmentation and Aggregation Attacks) research, which uncovered fundamental design flaws and widespread implementation vulnerabilities in the IEEE 802.11 Wi-Fi standard affecting virtually all Wi-Fi devices.

Critical Impact

An adversary within adjacent network range can inject arbitrary network packets, potentially enabling traffic manipulation, network reconnaissance, or facilitating further attacks independent of the network's encryption configuration.

Affected Products

• Samsung Galaxy S3 i9305 (Firmware 4.4.4)
• Arista C-Series Access Points (C-65, C-75, C-100, C-110, C-120, C-130, C-200, C-230, C-235, C-250, C-260)
• Arista O-Series Access Points (O-90, O-105)
• Arista W-Series Access Points (W-68, W-118)
• Siemens SCALANCE W700 IEEE 802.11ax/802.11n

Discovery Timeline

• May 11, 2021 - CVE-2020-26144 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-26144

Vulnerability Analysis

This vulnerability stems from improper input validation (CWE-20) in the frame aggregation handling of Wi-Fi implementations. The IEEE 802.11 standard defines A-MSDU as a method for aggregating multiple MSDUs into a single frame to improve throughput. However, vulnerable implementations fail to properly validate whether incoming A-MSDU frames are encrypted as required by the active security protocol.

The attack exploits a specific weakness where devices accept plaintext A-MSDU frames when the first 8 bytes match a valid RFC1042 LLC/SNAP header structure for EAPOL (Extensible Authentication Protocol over LAN). Since EAPOL frames are legitimately sent unencrypted during the authentication handshake, implementations incorrectly extend this exception to A-MSDU frames containing an EAPOL-like header prefix.

Root Cause

The root cause is insufficient validation in the Wi-Fi frame processing logic. Specifically, the frame type validation relies solely on inspecting the first 8 bytes of the frame payload rather than verifying the frame's encryption status against the current security association. This allows an attacker to craft malicious A-MSDU frames that bypass encryption requirements by simply prefixing them with an EAPOL-compatible LLC/SNAP header, while the actual injected content remains arbitrary.

Attack Vector

The attack requires the adversary to be within wireless range of the target device (adjacent network access). No authentication or user interaction is required to exploit this vulnerability. The attacker can:

1. Craft a plaintext A-MSDU frame with the first 8 bytes matching a valid RFC1042 LLC/SNAP header for EAPOL
2. Inject the malicious frame into the wireless network
3. Vulnerable devices will accept and process the frame despite not being properly encrypted
4. The adversary can inject arbitrary network packets, potentially including malicious payloads

The attack enables packet injection that works across all Wi-Fi security protocols (WEP, WPA, WPA2, and WPA3), as the vulnerability exists in the frame processing layer rather than the cryptographic implementation itself. For detailed technical analysis, refer to the FragAttacks Official Website and the GitHub FragAttacks Summary.

Detection Methods for CVE-2020-26144

Indicators of Compromise

• Unexpected plaintext A-MSDU frames appearing in wireless traffic captures
• Network traffic anomalies such as unexpected EAPOL frames outside of authentication sequences
• Unusual packet injection patterns or traffic that doesn't match expected encrypted frame formats
• Wireless IDS/IPS alerts for frame format violations or protocol anomalies

Detection Strategies

• Deploy wireless intrusion detection systems (WIDS) capable of monitoring 802.11 frame structures and flagging plaintext A-MSDU anomalies
• Analyze packet captures for A-MSDU frames with EAPOL LLC/SNAP headers that contain non-EAPOL payload content
• Monitor for unusual network behavior patterns that may indicate successful packet injection
• Implement network traffic analysis to detect unexpected broadcast or multicast traffic originating from wireless segments

Monitoring Recommendations

• Enable detailed wireless logging on access points and wireless controllers to capture frame-level metadata
• Deploy network monitoring solutions that can inspect 802.11 frame aggregation behavior
• Establish baseline wireless traffic patterns to identify anomalous injection attempts
• Consider deploying dedicated wireless security monitoring in high-security environments

How to Mitigate CVE-2020-26144

Immediate Actions Required

• Apply firmware updates from affected vendors immediately when available
• Review vendor security advisories: Arista Security Advisory #12602, Siemens Product Security Advisory, and Cisco Security Advisory
• Conduct an inventory of all wireless devices in the environment to identify affected equipment
• Prioritize patching of access points and infrastructure devices over endpoint devices

Patch Information

Vendors have released firmware updates to address this vulnerability as part of the broader FragAttacks remediation. Organizations should obtain patches directly from their device manufacturers:

• Samsung: Check for device firmware updates for Galaxy S3 i9305 devices
• Arista: Security Advisory #12602 provides patch information for C-Series, O-Series, and W-Series access points
• Siemens: SSA-913875 addresses SCALANCE W700 series devices
• Other vendors: Consult the Cisco Security Advisory and vendor-specific resources

Workarounds

• Ensure all client-to-access-point traffic uses HTTPS or other encrypted application-layer protocols to mitigate impact of potential packet injection
• Implement network segmentation to limit the blast radius of any successful exploitation
• Consider replacing end-of-life devices that will not receive security updates
• Monitor wireless environments for suspicious activity while awaiting patches

# Example: Check current firmware version on Arista access points
# Access the device CLI and verify firmware is updated to patched versions
show version
show system

# Verify wireless security configuration
show wlan security