POWER METER SICAM Q100: Session Fixation
CVE-2022-43398 is a high-severity session fixation vulnerability in POWER METER SICAM Q100 from Siemens, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected POWER METER SICAM Q100 versions: All versions < V2.50. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.6% 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 7kg9501-0aa01-2aa1 Firmware to 2.50 or a later version.
- Update 7kg9501-0aa31-2aa1 Firmware to 2.50 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.
- 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 | POWER METER SICAM Q100 | All versions < V2.50 | Not stated |
| Siemens | 7kg9501-0aa01-2aa1 Firmware | before 2.50 | 2.50 |
| Siemens | 7kg9501-0aa31-2aa1 Firmware | before 2.50 | 2.50 |
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
- 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:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (siemens.com) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
A vulnerability has been identified in POWER METER SICAM Q100 (All versions < V2.50), POWER METER SICAM Q100 (All versions < V2.50), POWER METER SICAM Q100 (All versions < V2.50), POWER METER SICAM Q100 (All versions < V2.50). Affected devices do not renew the session cookie after login/logout and also accept user defined session cookies. An attacker could overwrite the stored session cookie of a user. After the victim logged in, the attacker is given access to the user's account through the activated session.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Session Fixation
Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.
How developers prevent this class of flaw
- Invalidate any existing session identifiers prior to authorizing a new user session.
- For platforms such as ASP that do not generate new values for sessionid cookies, utilize a secondary cookie. In this approach, set a secondary cookie on the user's browser to a random value and set a session variable to the same value. If the session variable and the cookie value ever don't match, invalidate the session, and force the user to log on again.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other references
Other vulnerabilities in POWER METER SICAM Q100
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
Recent Session Fixation vulnerabilities
- 8.1 High severity
- 9.8 Critical severity
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.1 High severity
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