Full Report
SIMATIC S7-200 SMART devices contain an information disclosure vulnerability which leaves the system susceptible to a family of attacks which rely on the use of predictable IP ID sequence numbers as their base method of attack and eventually could allow an attacker to create a denial of service condition. Siemens recommends specific countermeasures for products where fixes are not, or not yet available.
Analysis Summary
# Vulnerability: Information Disclosure via Predictable IP ID Sequence in SIMATIC S7-200 SMART
## CVE Details
- CVE ID: CVE-2024-35292
- CVSS Score: 8.2 (High) based on CVSS v3.1; 8.8 (Critical) based on CVSS v4.0
- CWE: CWE-330: Use of Insufficiently Random Values
## Affected Systems
- Products: SIMATIC S7-200 SMART CPU series, including:
- CR40 (6ES7288-1CR40-0AA0)
- CR60 (6ES7288-1CR60-0AA0)
- SR20 (6ES7288-1SR20-0AA0, 6ES7288-1SR20-0AA1)
- SR30 (6ES7288-1SR30-0AA0, 6ES7288-1SR30-0AA1)
- SR40 (6ES7288-1SR40-0AA0, 6ES7288-1SR40-0AA1)
- SR60 (6ES7288-1SR60-0AA0, 6ES7288-1SR60-0AA1)
- ST20 (6ES7288-1ST20-0AA0)
- Versions: All versions of the listed products are affected.
- Configurations: Not specified, presumed default configurations.
## Vulnerability Description
The affected SIMATIC S7-200 SMART devices utilize a predictable sequence number for IP IDs. This information disclosure allows an unauthenticated, remote attacker to observe or guess the sequence, enabling them to base specific exploitation techniques (a family of attacks relying on this predictability) on this knowledge. The primary realized impact is the potential to cause a Denial of Service (DoS) condition against the device.
## Exploitation
- Status: The advisory implies the vulnerability is exploitable, referencing attacks based on predictable IP IDs. PoC availability is not explicitly stated but is implied by the existence of known attack families exploiting this weakness.
- Complexity: Low (CVSS v3.1: AC:L - Attack Complexity Low)
- Attack Vector: Network (CVSS v3.1: AV:N)
## Impact
- Confidentiality: Low (C:L) - Information disclosure related to IP ID sequence.
- Integrity: None (I:N)
- Availability: High (A:H) - Potential for Denial of Service (DoS).
## Remediation
### Patches
- No fix is currently planned for any affected CPU versions.
### Workarounds
- Apply countermeasures as recommended in Siemens' operational guidelines for industrial security:
- Implement network segmentation to isolate critical assets.
- Implement firewall rules and proper network security controls to strictly limit network access to the devices.
- Follow recommendations stated in the product manuals.
## Detection
- Detection methods primarily involve monitoring network traffic associated with the affected devices for suspicious patterns that might indicate attempts to exploit the predictable IP ID sequence, particularly high volumes of fragmented or specifically crafted packets attempting to exhaust resources leading to DoS.
- Specific IOCs related to the IP ID sequence manipulation should be derived from deeper analysis of the underlying attack family exploiting CWE-330.
## References
- Vendor Advisories:
- https://cert-portal.siemens.com/productcert/html/ssa-481506.html
- https://www.siemens.com/cert/operational-guidelines-industrial-security
- https://www.siemens.com/cert/advisories
- https://www.siemens.com/industrialsecurity