CVE-2023-5777

Executive Summary

CVE-2023-5777 is a critical vulnerability in Weintek EasyBuilder Pro, a widely used Human-Machine Interface (HMI) design and runtime software package for industrial control systems (ICS) and supervisory control and data acquisition (SCADA) environments. The flaw stems from the use of hard-coded credentials in the crash report transmission mechanism: even after the private key is deleted upon completion of the crash report upload, the key remains publicly exposed, allowing an unauthenticated remote attacker to obtain control of the crash report server. With a CVSS score of 9.8, successful exploitation grants an attacker full remote control of the crash report server, potentially leading to data exfiltration, malware deployment, or lateral movement into OT networks. Affected organizations are those operating Weintek HMI panels and engineering workstations running EasyBuilder Pro versions prior to the vendor's patch releases. No public exploit code or CISA KEV listing exists at the time of this report, but the severity and network accessibility of the flaw warrant immediate attention.

Technical Analysis

The vulnerability class is CWE-798: Use of Hard-coded Credentials. According to the NVD description, Weintek EasyBuilder Pro contains a flaw in its crash report transmission functionality. The mechanism involves a private key used to authenticate or encrypt communications between the EasyBuilder Pro client and the crash report server (a remote server operated by the vendor or a third party). The description states that "even when the private key is immediately deleted after the crash report transmission is finished, the private key is exposed to the public." This implies the private key is either:

1. Embedded in the client software binary and extractable via static analysis.
2. Transmitted or cached in a location accessible to the local user or to network observers.
3. Hard-coded in the protocol implementation and recoverable by reverse engineering the crash report transmission routine.

The criticality is compounded by the fact that deletion of the key after each transmission is insufficient — the key's exposure persists, meaning an attacker who obtains the key can impersonate the crash report server, intercept traffic, or gain full administrative control of the server-side crash report infrastructure. This is a classic key-management failure: the key is not rotated, not stored in a hardware security module (HSM), and not protected by access controls.

The CVSS 9.8 rating reflects: Network attack vector (AV:N), Low attack complexity (AC:L), No privileges required (PR:N), No user interaction (UI:N), and High impact on Confidentiality, Integrity, and Availability (C:H/I:H/A:H). The attack surface is the crash report server and any clients that communicate with it, which are typically HMI engineering workstations and possibly the HMI panels themselves if they transmit crash reports.

Technical detail beyond this is sparse. No specific function names, class names, endpoints, or file paths are provided in the NVD description or CNA title beyond "EasyBuilder Pro" and "crash report server." Therefore, code-level analysis is limited. What is known: an unauthenticated attacker with the exposed key can likely replay, forge, or intercept crash report communications, and the "remote control of the crash report server" phrase indicates the key unlocks server-side administrative functions.

The attack surface is not limited to a single host: any network-restricted environment where EasyBuilder Pro communicates with a crash report server is vulnerable. In ICS environments, such servers may be Internet-facing for telemetry, or reachable via corporate networks, expanding the blast radius to the OT domain if network segmentation is poor.

Exploitation Scenarios

No public PoC or exploit code is currently available; the following attack chain is inferred from the vulnerability class and the NVD description.

Step 1 — Reconnaissance and Target Identification An attacker begins by identifying Weintek EasyBuilder Pro installations. This can be accomplished via Shodan or Censys searches for HMI panels, engineering workstations running Weintek software, or crash report servers responding to expected protocol handshakes. The Shodan dorks provided in the metadata may help locate exposed assets. Alternatively, the attacker targets an organization's network after initial access (e.g., via phishing) and scans for EasyBuilder Pro processes or related services on internal segments.

Step 2 — Triggering the Flaw The attacker obtains the exposed private key. Because the key is "exposed to the public," it may be recoverable by:

• Extracting it from the EasyBuilder Pro binary installed on a compromised engineering workstation.
• Capturing it from network traffic if the key is transmitted in plaintext or in a recoverable form.
• Downloading it from a public repository or forum where security researchers or accidental disclosures have posted it.

Once in possession of the key, the attacker can initiate a connection to the crash report server, impersonating a legitimate client or server, depending on the protocol architecture.

Step 3 — Payload/Execution Method At the vulnerability-class level, the attacker uses the hard-coded credential to authenticate to the crash report server with elevated privileges. This may involve:

• Authenticating to the server API or management interface using the exposed key.
• Forging crash reports that include malicious payloads (e.g., a crafted crash dump containing executable sections) that the server processes, triggering code execution.
• Intercepting and modifying crash report traffic (man-in-the-middle) if the key is used for encryption, allowing the attacker to inject commands.

The exact execution method depends on implementation details not disclosed in the NVD description. The outcome is "obtaining remote control of the crash report server," which implies the key grants sufficient privileges to run commands, modify server configuration, or exfiltrate stored crash data.

Step 4 — Post-Exploitation Impact Once the crash report server is compromised, the attacker can:

• Access sensitive technical data from crash reports (including potentially memory dumps from engineering workstations, which may contain credentials, control logic, or proprietary configuration data).
• Deploy malware (e.g., ransomware, Remote Access Trojans) on the server, which may be co-located or networked with other ICS infrastructure.
• Use the server as a pivot point to move laterally within the OT/IT network, especially if the crash report server has elevated privileges or is domain-joined.
• Trigger further propagation by pushing malicious firmware or configuration updates to HMI panels if the server has update-management capabilities.

The high Availability impact (A:H) suggests the attacker could also disrupt crash report processing, potentially causing denial-of-service conditions in monitoring operations.

Impact Assessment

Business Impact: The vulnerability targets industrial control systems, which are critical infrastructure. A compromised crash report server can lead to downtime, production halts, or safety incidents if attackers manipulate HMI functionality or plant-wide visibility tools. The exposed private key undermines trust in the entire crash report ecosystem, and the 9.8 CVSS score underscores that full system compromise is feasible with minimal attacker skill or resources.

Affected Systems: Weintek EasyBuilder Pro versions prior to v6.08.01.614 and v6.08.02.500. This includes engineering workstations running the software and any associated crash report servers (vendor-hosted or self-hosted). The HMI panels that transmit crash reports are also indirectly affected.

Blast Radius: If the crash report server is Internet-facing, the blast radius is global — any attacker can target it without network access. In segmented environments, the initial compromise may be limited to the server, but lateral movement into OT networks is plausible given common flat-network topologies in legacy industrial environments. The CVSS subscores (C:H/I:H/A:H) indicate complete loss of confidentiality, integrity, and availability of the compromised server.

Attacker Motivation: Likely actors include state-sponsored cyber units targeting critical infrastructure, hacktivists seeking disruption, and financially motivated criminals (e.g., ransomware gangs). The lack of public PoC suggests the flaw has not yet been weaponized, but it is a trivial-to-moderate reverse engineering effort to extract the exposed key.

Detection Guidance

The following detection rules are generic and based on the vulnerability class. Since specific endpoints, file paths, or protocol details are unknown, they focus on behavior patterns observable during exploitation attempts, such as suspicious authentication to crash report services or unusual network traffic to Weintek-associated services.

Sigma Rule

title: CVE-2023-5777 - Weintek EasyBuilder Pro Suspicious Crash Report Authentication
id: 5f4f142a-1b83-4f6d-9e6c-3a6d2b8f9c1a
status: experimental
description: Detects unusual authentication attempts to Weintek EasyBuilder Pro crash report servers, potentially indicating use of exposed hard-coded credentials.
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2023-5777
logsource:
    product: windows
    service: security
detection:
    selection_auth:
        EventID: 4625  # Failed logon
        LogonType: 3   # Network logon
        ProcessName: '*EasyBuilder*'
    selection_success:
        EventID: 4624  # Successful logon
        LogonType: 3
        ProcessName: '*EasyBuilder*'
    condition: selection_auth or selection_success
    timeframe: 10m
falsepositives:
    - Legitimate crash report uploads from multiple engineering workstations
    - Scheduled maintenance tasks
level: medium
tags:
    - attack.initial-access
    - attack.t1190
    - cve.2023-5777

YARA Rule

rule CVE_2023_5777_Weintek_EasyBuilder_Key_Exposure {
    meta:
        author = "Valtersit Threat Intel"
        date = "2025-03-24"
        description = "Detects strings or byte patterns associated with the exposed private key or crash report authentication in Weintek EasyBuilder Pro binaries."
        cve = "CVE-2023-5777"
        severity = "critical"
    strings:
        $key_marker1 = "crash_report_private_key" ascii wide nocase
        $key_marker2 = "EasyBuilderPro_CrashKey" ascii wide nocase
        $key_marker3 = "ServerAuthToken=" ascii wide nocase
        $key_hex = { 30 31 32 33 34 35 36 37 } // Generic hex key pattern, adjust as needed
        $server_url = "crashreport.weintek.com" ascii wide nocase
    condition:
        uint16(0) == 0x5A4D and  // PE magic
        (any of ($key_marker*)) or
        ($server_url and 1 of ($key_*))
}

Suricata IDS Rule

alert tcp any any -> any 8080 (msg:"CVE-2023-5777 - Weintek EasyBuilder Pro Crash Report Server Authentication Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/crashreport"; http_uri; content:"Authorization"; http_header; pcre:"/Basic [A-Za-z0-9+\/]+={0,2}/"; classtype:attempted-admin; sid:20235777; rev:1; reference:cve,2023-5777;)

Elastic Detection

sequence by process.entity_id with maxspan=10m
  [process where process.name == "EasyBuilder.exe" and
   event.action == "network_connection" and
   network.protocol == "http" and
   destination.domain == "crashreport.weintek.com"]
  [authentication where event.action == "authentication_success" and
   user.name != "SYSTEM" and
   process.name == "EasyBuilder.exe"]

Splunk SPL Query

index=windows sourcetype=WinEventLog:Security
| search (LogonType=3 AND (ProcessName="*EasyBuilder*" OR ProcessName="*HMI*"))
| eval is_auth = if(match(EventCode, "^4624$|^4625$"), 1, 0)
| where is_auth=1
| stats count by src_ip, dest_ip, user, EventCode, _time
| sort - _time
| table _time, src_ip, dest_ip, user, EventCode, count

Wazuh OSSEC Rule

<group name="weintek_cve_2023_5777,">
    <rule id="100577" level="12">
        <if_sid>5715</if_sid>
        <field name="win.eventdata.processName">\.*EasyBuilder*\.</field>
        <field name="win.system.eventID">^4625$</field>
        <description>CVE-2023-5777 - Multiple failed network logon attempts by EasyBuilder Pro process</description>
        <mitre><id>T1190</id></mitre>
        <group>authentication_failures,</group>
    </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence: 2/4 (CLAIMED) — The CNA (Weintek) has issued a patch, but the fix is not independently confirmed. Treat the vendor advisory as authoritative but verify the fix in your environment.

1. Immediate Mitigations (If Patch Cannot Be Applied Immediately):

• Disable or restrict the crash report transmission feature in EasyBuilder Pro if not required for compliance or support.
• Block outbound network traffic from engineering workstations and HMI panels to the crash report server URLs (e.g., https://crashreport.weintek.com) at the firewall or via egress filtering.
• Implement network segmentation: isolate HMI engineering workstations from the Internet and from the broader OT network; place them on a dedicated management VLAN.
• Monitor authentication logs for anomalous crash report-related logins; the exposed key should be treated as compromised — enforce strict logging of all server-side access.
• Place the crash report server behind a reverse proxy that enforces multi-factor authentication (MFA), if feasible.

2. Patch/Upgrade Steps:

• Download and install EasyBuilder Pro v6.08.01.614 or v6.08.02.500 from the vendor's official download portal:
  • https://www.weintek.com/globalw/Download/Download.aspx
• Before upgrading, verify the integrity of the installer via the vendor-provided checksums (if available).
• Roll out the update first to non-production or test engineering workstations, then to production systems, coordinating with change-management procedures to minimize downtime.
• After the update, validate that crash report functionality operates correctly and that the private key is no longer exposed (e.g., by inspecting the application binaries for previous key material).

3. Long-Term Hardening:

• Rotate all credentials associated with crash report infrastructure, even after patching, as the private key may have been exposed to third parties (e.g., security researchers, malicious actors) prior to the patch.
• Establish a cryptographic key management policy: use HSM-backed keys where possible, and enforce automated key rotation for any externally accessible services.
• Conduct periodic security audits of all ICS software components, focusing on hard-coded credential classes.
• Improve network visibility with Intrusion Detection Systems (IDS) placed in OT network segments, tuned to the rules above.
• Engage with Weintek's support for a deeper advisory or CVE coordination updates, as patch confirmation is pending.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2023-5777 — Official NVD details and description.
2. Weintek Vendor Advisory: https://www.weintek.com/globalw/Download/Download.aspx — Vendor download portal containing patched versions referenced in the CNA data.
3. CWE-798 Reference: https://cwe.mitre.org/data/definitions/798.html — Weakness class documentation for hard-coded credentials.
4. Weintek Product Page: https://www.weintek.com/globalw/Product/Product.aspx — Information on EasyBuilder Pro and Weintek HMI products.

Exploit-in-the-Wild Evidence: None known at the time of this report. The CVE is NOT listed in the CISA Known Exploited Vulnerabilities catalog. No public exploit code, PoC, or threat actor campaigns have been identified. EPSS score (0.00536) suggests low immediate exploitation likelihood, but the CVSS 9.8 severity and straightforward vulnerability class make weaponization plausible in the near term once more details are disclosed or reverse-engineered.