SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: Use After Free
CVE-2022-43680 is a high-severity use after free vulnerability in SIMATIC S7-1500 CPU 1518-4 PN/DP MFP from Siemens, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version V3.1.5 as the first without the flaw, so updating SIMATIC S7-1500 CPU 1518-4 PN/DP MFP to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 3.2% chance of exploitation within 30 days, higher than 88% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update SIMATIC S7-1500 CPU 1518-4 PN/DP MFP to V3.1.5 or a later version.
- Update SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP to V3.1.5 or a later version.
- Update SIPLUS S7-1500 CPU 1518-4 PN/DP MFP to V3.1.5 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP | V3.1.0 up to, but not including, V3.1.5 | V3.1.5 |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP | V3.1.0 up to, but not including, V3.1.5 | V3.1.5 |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP | V3.1.0 up to, but not including, V3.1.5 | V3.1.5 |
| Libexpat Project | Libexpat | 2.4.9 and earlier | Not stated |
| Debian | Debian Linux | 10.0; 11.0 | Not stated |
| Fedora Project | Fedora | 35; 36; 37 | Not stated |
| NetApp | H300s Firmware | Not specified in the record | Not stated |
| NetApp | H500s Firmware | Not specified in the record | Not stated |
| NetApp | H700s Firmware | Not specified in the record | Not stated |
| NetApp | H410s Firmware | Not specified in the record | Not stated |
| NetApp | H410c Firmware | Not specified in the record | Not stated |
| NetApp | Active Iq Unified Manager | Not specified in the record | Not stated |
| NetApp | Oncommand Workflow Automation | Not specified in the record | Not stated |
| NetApp | Solidfire & Hci Management Node | Not specified in the record | Not stated |
| NetApp | Hci Compute Node Firmware | Not specified in the record | Not stated |
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
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 3.1 | 7.5 | High | CISA (ADP) |
Official description
In libexpat through 2.4.9, there is a use-after free caused by overeager destruction of a shared DTD in XML_ExternalEntityParserCreate in out-of-memory situations.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/libexpat/libexpat/issues/649Exploit, Issue Tracking, Third Party Advisory
- github.com/libexpat/libexpat/pull/616Exploit, Issue Tracking, Third Party Advisory
- github.com/libexpat/libexpat/pull/650Exploit, Issue Tracking, Third Party Advisory
Third-party and government advisories
- openwall.com/lists/oss-security/2023/12/28/5Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2024/01/03/5Mailing List, Third Party Advisory
- lists.debian.org/debian-lts-announce/2022/10/msg00033.htmlMailing List, Third Party Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AJ5VY2VYXE4WTRGQ6LMG…Mailing List, Third Party Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BY4OPSIB33ETNUXZY2UP…Mailing List, Third Party Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DPQVIF6TOJNY2T3ZZETF…Mailing List, Third Party Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FFCOMBSOJKLIKCGCJWHL…Mailing List, Third Party Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IUJ2BULJTZ2BMSKQHB6U…Mailing List, Third Party Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XG5XOOB7CD55CEE6OJYK…Mailing List, Third Party Advisory
- security.gentoo.org/glsa/202210-38Third Party Advisory
- security.netapp.com/advisory/ntap-20221118-0007/Third Party Advisory
- debian.org/security/2022/dsa-5266Third Party Advisory
Other references
Other vulnerabilities in SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
- 9.6 Critical severity
- 9.6 Critical severity
- 9.6 Critical severity
- 7.8 High severity
- 7.1 High severity
- 9.1 Critical severity
Recent Use After Free vulnerabilities
- 7.0 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.5 High severity
- 9.8 Critical severity
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