CVE-2024-7755: EWON FLEXY 202 Credential Exposure Flaw

CVE-2024-7755 Overview

CVE-2024-7755 affects the EWON FLEXY 202 industrial gateway. The device transmits user credentials using Base64 encoding rather than a cryptographic protocol. Base64 is an encoding scheme, not encryption, and any party with network access can decode the values. An attacker positioned on the network can passively capture traffic and recover plaintext credentials. The weakness is classified under CWE-522: Insufficiently Protected Credentials. The flaw is relevant to operational technology (OT) environments where the FLEXY 202 provides remote access to industrial control systems.

Critical Impact
Network-adjacent attackers can sniff traffic, decode Base64-encoded credentials, and obtain authenticated access to the EWON FLEXY 202 gateway and connected industrial assets.

Affected Products

EWON FLEXY 202 industrial remote access gateway
Deployments routing management traffic over untrusted or shared networks
OT environments using the FLEXY 202 for VPN or remote maintenance sessions

Discovery Timeline

2024-10-17 - CVE-2024-7755 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-7755

Vulnerability Analysis

The EWON FLEXY 202 is a remote access gateway used in industrial automation deployments. The device authenticates users and transmits those credentials across the network. According to the advisory, the credentials are encoded with Base64 rather than protected by transport encryption or a challenge-response scheme.

Base64 is a reversible encoding format. Any attacker capturing the byte sequence can run a standard decode routine and recover the original username and password. No cryptographic key, brute force, or offline cracking step is required. The vulnerability is exploitable from the network when an attacker can observe the relevant session, for example through ARP spoofing, switch-port mirroring, a rogue access point, or any other man-in-the-middle position.

Root Cause

The root cause is the use of an encoding function in place of a security control. Base64 produces output that looks opaque but provides no confidentiality. The credential transport channel lacks TLS or an equivalent protocol to protect data in transit. This pattern maps directly to CWE-522: Insufficiently Protected Credentials.

Attack Vector

An attacker on the same broadcast domain or any segment carrying FLEXY 202 management traffic captures packets using a standard sniffer such as tcpdump or Wireshark. The attacker locates the authentication request, extracts the Base64 string, and decodes it with a single command such as echo <string> | base64 -d. The recovered credentials enable login to the gateway and access to downstream industrial assets, including PLCs reachable through the device.

No exploit code is required. The vulnerability mechanism is described in the CISA ICS Advisory ICSA-24-291-04.

Detection Methods for CVE-2024-7755

Indicators of Compromise

Unexpected authenticated sessions to the FLEXY 202 web or management interface from unfamiliar source addresses.
Repeated administrative logins outside of scheduled maintenance windows.
Configuration changes to VPN tunnels, user accounts, or remote access policies on the gateway.
ARP table anomalies on switches carrying FLEXY 202 traffic, indicating possible man-in-the-middle activity.

Detection Strategies

Inspect traffic to and from the FLEXY 202 for cleartext or Base64-encoded credential fields in HTTP request bodies and headers.
Alert on management protocol sessions sourced from non-engineering workstations or untrusted VLANs.
Baseline normal authentication patterns for the device and flag deviations in source IP, time of day, or session frequency.

Monitoring Recommendations

Forward network flow records and gateway logs to a SIEM for correlation with identity events.
Enable port mirroring on switches connected to the FLEXY 202 and route copies to an IDS configured with rules for ARP spoofing and credential reuse.
Audit the device administrative account list on a recurring basis to identify unauthorized additions.

How to Mitigate CVE-2024-7755

Immediate Actions Required

Isolate the FLEXY 202 on a dedicated management VLAN reachable only from authorized engineering workstations.
Rotate all FLEXY 202 administrative and user credentials, assuming prior traffic may have been captured.
Restrict remote access to the device to encrypted channels such as an external VPN concentrator that terminates TLS or IPsec before reaching the gateway.
Review the CISA ICS Advisory ICSA-24-291-04 and apply vendor-provided guidance.

Patch Information

Refer to HMS Networks and the CISA ICS Advisory ICSA-24-291-04 for firmware updates and mitigation guidance specific to the EWON FLEXY 202. Apply firmware updates following standard OT change control procedures.

Workarounds

Place the gateway behind a network segment that enforces TLS termination or an IPsec tunnel for all management traffic.
Disable any unused remote access features and management interfaces on the device.
Restrict source IP addresses permitted to reach the management interface through firewall rules at the cell or zone boundary.
Monitor the segment for ARP spoofing and other man-in-the-middle indicators using an OT-aware intrusion detection system.

bash

# Example firewall restriction limiting management access to a jump host
iptables -A FORWARD -s 10.10.20.5 -d 10.10.50.10 -p tcp --dport 443 -j ACCEPT
iptables -A FORWARD -d 10.10.50.10 -p tcp --dport 443 -j DROP