CPC80 Central Processing/Communication: Improper Null Termination
CVE-2024-31484 is a high-severity improper null termination vulnerability in CPC80 Central Processing/Communication from Siemens, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions V16.41, 16.41 as the first without the flaw, so updating CPC80 Central Processing/Communication to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.47% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update CPC80 Central Processing/Communication to V16.41 or 16.41, whichever matches your release line, or a later version.
- Update CPCI85 Central Processing/Communication to V5.30 or 5.30, whichever matches your release line, or a later version.
- Update CPCX26 Central Processing/Communication to V06.02 or a later version.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Siemens | CPC80 Central Processing/Communication | before V16.41; before 16.41 | V16.41, 16.41 |
| Siemens | CPCI85 Central Processing/Communication | before V5.30; before 5.30 | V5.30, 5.30 |
| Siemens | CPCX26 Central Processing/Communication | before V06.02 | V06.02 |
| Siemens | ETA4 Ethernet Interface IEC60870-5-104 | before V10.46 | V10.46 |
| Siemens | ETA5 Ethernet Int. 1x100TX IEC61850 Ed.2 | before V03.27 | V03.27 |
| Siemens | PCCX26 Ax 1703 PE, Contr, Communication Element | before V06.05 | V06.05 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CNA (siemens.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.3 | High | CNA (siemens.com) |
| CVSS 3.1 | 7.8 | High | CNA (siemens.com) |
Official description
A vulnerability has been identified in CPC80 Central Processing/Communication (All versions < V16.41), CPCI85 Central Processing/Communication (All versions < V5.30), CPCX26 Central Processing/Communication (All versions < V06.02), ETA4 Ethernet Interface IEC60870-5-104 (All versions < V10.46), ETA5 Ethernet Int. 1x100TX IEC61850 Ed.2 (All versions < V03.27), PCCX26 Ax 1703 PE, Contr, Communication Element (All versions < V06.05). The affected devices contain an improper null termination vulnerability while parsing a specific HTTP header. This could allow an attacker to execute code in the context of the current process or lead to denial of service condition.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Null Termination
The product does not terminate or incorrectly terminates a string or array with a null character or equivalent terminator.
How developers prevent this class of flaw
- Use a language that is not susceptible to these issues. However, be careful of null byte interaction errors (CWE-626) with lower-level constructs that may be written in a language that is susceptible.
- Ensure that all string functions used are understood fully as to how they append null characters. Also, be wary of off-by-one errors when appending nulls to the end of strings.
- If performance constraints permit, special code can be added that validates null-termination of string buffers, this is a rather naive and error-prone solution.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in CPC80 Central Processing/Communication
- 9.0 Critical severity
Recent Improper Null Termination vulnerabilities
- 7.5 High severity
- 7.5 High severity
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