---
title: "Critical Buffer Overflow Flaw in ABB AC500 V3 PLCs Threatens Industrial Systems"
short_title: "Critical flaw in ABB AC500 V3 PLCs risks RCE"
description: "ABB AC500 V3 PLCs affected by a critical stack buffer overflow vulnerability (CVE-2025-15467). Patch now to prevent DoS, crashes, or remote code execution."
author: "Vitus"
date: 2025-01-24
categories: [Cybersecurity, Vulnerabilities]
tags: [abb, plc, cve-2025-15467, buffer-overflow, industrial-security]
score: 0.92
cve_ids: [CVE-2025-15467]
---
## TL;DR
ABB has disclosed a critical stack buffer overflow vulnerability (CVE-2025-15467) in its AC500 V3 PLCs, affecting firmware versions 3.9.0 and 3.9.0_HF1. If exploited, this flaw could lead to denial-of-service (DoS), system crashes, or remote code execution (RCE). A patch is available, and ABB urges users to update immediately to mitigate risks to industrial control systems (ICS) in critical sectors like energy, manufacturing, and water treatment.
Main Content
### Critical Vulnerability in ABB AC500 V3 PLCs Exposes Industrial Systems to Attacks
ABB, a global leader in industrial automation, has issued an urgent security advisory addressing a severe stack buffer overflow vulnerability in its AC500 V3 programmable logic controllers (PLCs). Tracked as CVE-2025-15467, this flaw carries a CVSS score of 9.8, classifying it as critical. The vulnerability affects PLCs deployed in chemical, energy, manufacturing, and water/wastewater sectors worldwide, raising concerns about potential disruptions to critical infrastructure.
### Key Points
- Vulnerability: Stack buffer overflow in the Cryptographic Message Syntax (CMS) parsing mechanism of ABB AC500 V3 PLCs.
- Impact: Exploitation could lead to system crashes, DoS, or RCE, allowing attackers to take control of affected devices.
- Affected Versions: AC500 V3 PM5xxx firmware versions 3.9.0 and 3.9.0_HF1.
- Patch Available: ABB has released firmware version 3.9.0 HF1 to address the issue. Users are advised to update immediately.
- Exploitation Risk: No valid key material is required to trigger the flaw, making it easier for attackers to exploit.
### Technical Details
The vulnerability stems from the improper handling of CMS (Auth)EnvelopedData structures that use AEAD ciphers like AES-GCM. When parsing these structures, the Initialization Vector (IV) encoded in the ASN.1 parameters is copied into a fixed-size stack buffer without validating its length. An attacker can craft a malicious CMS message with an oversized IV, triggering a stack-based out-of-bounds write before authentication or tag verification occurs.
#### Why This Is Dangerous
- Pre-Authentication Exploit: The overflow occurs before authentication, meaning attackers do not need valid key material to exploit the flaw.
- Severe Impact: While exploitability for RCE depends on platform and toolchain mitigations, the stack-based write primitive represents a high-risk threat to industrial systems.
- Remote Exploitation: Attackers with network access to an affected PLC can exploit the vulnerability remotely, increasing the risk of widespread attacks.
### Impact Assessment
The AC500 V3 PLCs are widely used in industrial environments, including:
- Chemical plants
- Energy grids
- Critical manufacturing facilities
- Water and wastewater treatment systems
A successful exploit could lead to:
- Operational disruptions due to system crashes or DoS attacks.
- Unauthorized control of industrial processes, posing safety risks.
- Data breaches or manipulation of sensitive industrial data.
Given the global deployment of these PLCs, the potential for large-scale disruptions is significant. Organizations in affected sectors must prioritize patching to avoid catastrophic consequences.
### Attack Vector
- Remote Exploitation: Attackers with network access to an affected PLC can send a crafted CMS message to trigger the vulnerability.
- No User Interaction Required: The flaw can be exploited without any user interaction, increasing the likelihood of automated attacks.
- Low Attack Complexity: The vulnerability is easy to exploit, as it does not require advanced technical skills or valid credentials.
### Mitigation Steps
ABB has provided the following recommendations to mitigate the risk:
#### 1. Apply the Patch Immediately
- Update to AC500 V3 firmware version 3.9.0 HF1, which resolves the vulnerability.
- The firmware is available for download from the ABB Library.
#### 2. Network Segmentation
- Isolate control systems from business networks using firewalls.
- Minimize network exposure for all control system devices to reduce attack surfaces.
#### 3. Secure Remote Access
- Use Virtual Private Networks (VPNs) for remote access, ensuring they are updated to the latest version.
- Recognize that VPNs are only as secure as the devices connected to them.
#### 4. Follow Best Practices
- Refer to ABB’s General Security Recommendations for additional guidance on securing industrial systems.
- Implement CISA’s recommended cybersecurity strategies for proactive defense of ICS assets.
#### 5. Monitor for Suspicious Activity
- Organizations should monitor their networks for signs of exploitation and report any suspicious activity to CISA or ABB’s PSIRT.
### Affected Systems
| Vendor | Product | Affected Versions | Status |
|------------|--------------------------------------------------|-------------------------------------|---------------------|
| ABB | AC500 V3 PM5xxx PLCs | 3.9.0, 3.9.0_HF1 | Fixed in 3.9.0 HF1 |
## Conclusion
The CVE-2025-15467 vulnerability in ABB AC500 V3 PLCs represents a critical threat to industrial control systems worldwide. With a CVSS score of 9.8, the flaw could enable attackers to crash systems, disrupt operations, or execute remote code, posing severe risks to critical infrastructure. Organizations using affected PLCs must apply the patch immediately and implement network segmentation, secure remote access, and monitoring to mitigate risks.
As industrial systems become increasingly connected, vulnerabilities like this underscore the importance of proactive cybersecurity measures to safeguard against evolving threats. Stay vigilant, update systems, and follow best practices to protect critical operations.
## References
[^1]: ABB. "Security Advisory: AC500 V3 Stack Buffer Overflow in Cryptographic Message Syntax". Retrieved 2025-01-24.
[^2]: CISA. "ICS Advisory (ICSA-26-132-05): ABB AC500 V3 Stack Buffer Overflow". Retrieved 2025-01-24.
[^3]: CVE. "CVE-2025-15467 Detail". Retrieved 2025-01-24.
[^4]: MITRE. "CWE-787: Out-of-bounds Write". Retrieved 2025-01-24.