CVE-2023-42769

Q: What is the severity of CVE-2023-42769?

CVE-2023-42769 has a CVSS score of 9.8 (CRITICAL). This vulnerability allows attackers to brute-force weak session IDs, potentially hijacking authenticated sessions and bypassing authentication controls. It affects systems using Sielco's Winlog SCADA software with insufficient session ID entropy. Industrial control systems using this software are at risk.

9.8 CRITICAL

Authentication Bypass

📋 TL;DR

This vulnerability allows attackers to brute-force weak session IDs, potentially hijacking authenticated sessions and bypassing authentication controls. It affects systems using Sielco's Winlog SCADA software with insufficient session ID entropy. Industrial control systems using this software are at risk.

💻 Affected Systems

Products:

Sielco Winlog SCADA

Versions: All versions prior to 3.1.24

Operating Systems: Windows

Default Config Vulnerable: ⚠️ Yes

Notes: Affects Winlog SCADA installations with default session ID configuration. Industrial control systems using this software are vulnerable.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system compromise allowing attackers to manipulate industrial processes, disrupt operations, or cause physical damage through unauthorized control of SCADA systems.

🟠

Likely Case

Session hijacking leading to unauthorized access to SCADA interfaces, data theft, and potential manipulation of industrial parameters.

🟢

If Mitigated

Limited impact with proper network segmentation, monitoring, and compensating controls preventing brute-force attempts.

🌐 Internet-Facing: HIGH - If exposed to internet, attackers can remotely brute-force sessions without authentication.

🏢 Internal Only: MEDIUM - Internal attackers or compromised internal systems could exploit this, but requires network access.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Brute-force attacks require no authentication and can be automated with simple tools. Session ID length is insufficient for security.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Winlog SCADA 3.1.24

Vendor Advisory: https://www.sielco.org/en/contacts

Restart Required: Yes

Instructions:

1. Download Winlog SCADA 3.1.24 from Sielco. 2. Backup current installation. 3. Install the update following vendor instructions. 4. Restart the Winlog SCADA service. 5. Verify session IDs now have sufficient length.

🔧 Temporary Workarounds

Network Segmentation

all

Isolate Winlog SCADA systems from untrusted networks to prevent remote brute-force attacks.

Session Timeout Reduction

windows

Reduce session timeout values to limit window for brute-force attacks.

Configure in Winlog SCADA settings: Session timeout = 15 minutes or less

🧯 If You Can't Patch

Implement strict network access controls allowing only trusted IP addresses to access Winlog SCADA interfaces.
Deploy web application firewall (WAF) with rate limiting and session protection rules to detect/prevent brute-force attempts.

🔍 How to Verify

Check if Vulnerable:

Check Winlog SCADA version. If below 3.1.24, examine session ID length in application logs or network traffic - IDs shorter than 128 bits indicate vulnerability.

Check Version:

Check Winlog SCADA About dialog or installation directory version information.

Verify Fix Applied:

After patching, verify version is 3.1.24+ and session IDs in logs/network traffic show increased length and entropy.

📡 Detection & Monitoring

Log Indicators:

Multiple failed session attempts from single IP
Successful session from unusual IP after many failures
Session ID values showing predictable patterns

Network Indicators:

High volume of HTTP requests to session endpoints
Rapid sequential session ID guessing attempts

SIEM Query:

source="winlog_scada" AND (event="session_failure" count>10 per src_ip per 5min OR event="session_success" after multiple failures)

📊 Metadata

CVE ID: CVE-2023-42769

CVSS v3 Score: 9.8 (CRITICAL)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-284

Published: October 26, 2023

Last Updated: November 21, 2024

🔗 References

https://www.cisa.gov/news-events/ics-advisories/icsa-23-299-08 Third Party Advisory,US Government Resource
https://www.sielco.org/en/contacts Product
https://www.cisa.gov/news-events/ics-advisories/icsa-23-299-08 Third Party Advisory,US Government Resource
https://www.sielco.org/en/contacts Product

📋 TL;DR

💻 Affected Systems

📦 What is this software?

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Analog Fm Transmitter Exc1600gx Firmware by Sielco

Analog Fm Transmitter Exc2000gx Firmware by Sielco

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Analog Fm Transmitter Exc300gt Firmware by Sielco

Analog Fm Transmitter Exc300gx Firmware by Sielco

Analog Fm Transmitter Exc30gt Firmware by Sielco

Analog Fm Transmitter Exc5000gt Firmware by Sielco

Analog Fm Transmitter Exc5000gx Firmware by Sielco

Analog Fm Transmitter Exc5000gx Firmware by Sielco

Radio Link Exc19 Firmware by Sielco

Radio Link Exc19 Firmware by Sielco

Radio Link Rtx19 Firmware by Sielco

Radio Link Rtx19 Firmware by Sielco

Radio Link Rtx19 Firmware by Sielco

Radio Link Rtx19 Firmware by Sielco

⚠️ Risk & Real-World Impact

Worst Case

Likely Case

If Mitigated

🎯 Exploit Status

🛠️ Fix & Mitigation

✅ Official Fix

Instructions:

🔧 Temporary Workarounds

Network Segmentation

Session Timeout Reduction

🧯 If You Can't Patch

🔍 How to Verify

Check if Vulnerable:

Check Version:

Verify Fix Applied:

📡 Detection & Monitoring

Log Indicators:

Network Indicators:

SIEM Query:

📊 Metadata

🔗 References

📤 Share & Export

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