SIMATIC CP 1242-7 V2: Improper Encoding or Escaping of Output
CVE-2022-34820 is a critical-severity improper encoding or escaping of output vulnerability in SIMATIC CP 1242-7 V2 from Siemens, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected SIMATIC CP 1242-7 V2 versions: All versions < V3.3.46. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 2.27% chance of exploitation within 30 days, higher than 83% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Simatic Cp 1242-7 V2 Firmware to 3.3.46 or a later version.
- Update Simatic Cp 1243-1 Firmware to 3.3.46 or a later version.
- Update Simatic Cp 1243-7 Lte Eu Firmware to 3.3.46 or a later version.
- Read the advisory on cert-portal.siemens.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 5 further products are omitted here. 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
- 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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.4 | High | CNA (siemens.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
| CVSS 2.0 | 9.3 | High | NVD |
Official description
A vulnerability has been identified in SIMATIC CP 1242-7 V2 (All versions < V3.3.46), SIMATIC CP 1243-1 (All versions < V3.3.46), SIMATIC CP 1243-7 LTE EU (All versions < V3.3.46), SIMATIC CP 1243-7 LTE US (All versions < V3.3.46), SIMATIC CP 1243-8 IRC (All versions < V3.3.46), SIMATIC CP 1542SP-1 IRC (All versions >= V2.0 < V2.2.28), SIMATIC CP 1543-1 (All versions < V3.0.22), SIMATIC CP 1543SP-1 (All versions >= V2.0 < V2.2.28), SIPLUS ET 200SP CP 1542SP-1 IRC TX RAIL (All versions >= V2.0 < V2.2.28), SIPLUS ET 200SP CP 1543SP-1 ISEC (All versions >= V2.0 < V2.2.28), SIPLUS ET 200SP CP 1543SP-1 ISEC TX RAIL (All versions >= V2.0 < V2.2.28), SIPLUS NET CP 1242-7 V2 (All versions < V3.3.46), SIPLUS NET CP 1543-1 (All versions < V3.0.22), SIPLUS S7-1200 CP 1243-1 (All versions < V3.3.46), SIPLUS S7-1200 CP 1243-1 RAIL (All versions < V3.3.46). The application does not correctly escape some user provided fields during the authentication process. This could allow an attacker to inject custom commands and execute arbitrary code with elevated privileges.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Encoding or Escaping of Output
The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.
How developers prevent this class of flaw
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using the ESAPI Encoding control or a similar tool, library, or framework. These will help the programmer encode outputs in a manner less prone to error. Alternately, use built-in functions, but consider using wrappers in case those functions are discovered to have a vulnerability.
- If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated. For example, stored procedures can enforce database query structure and reduce the likelihood of SQL injection.
- Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages. Study all expected communication protocols and data representations to determine the required encoding strategies.
More Improper Encoding or Escaping of Output vulnerabilities (CWE-116)
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 vulnerabilities in SIMATIC CP 1242-7 V2
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 9.8 Critical severity
- 10.0 Critical severity
Recent Improper Encoding or Escaping of Output vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 9.8 Critical severity
- 8.1 High severity
- 9.8 Critical severity
- 6.1 Medium severity
Spotted an error? Tell us.