CyberSecBulletin
CVE-2022-26647NVD status: Modified

SCALANCE X200-4P IRT: Use of Insufficiently Random Values

Published Updated By the CyberSecBulletin desk

CVE-2022-26647 is a critical-severity use of insufficiently random values vulnerability in SCALANCE X200-4P IRT 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 SCALANCE X200-4P IRT versions: All versions < V5.5.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.2% chance of exploitation within 30 days, higher than 69% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Scalance X204-2 Firmware to 5.2.6 or a later version.
  2. Update Scalance X204-2fm Firmware to 5.2.6 or a later version.
  3. Update Scalance X204-2ld Firmware to 5.2.6 or a later version.
  4. Read the advisory on cert-portal.siemens.com for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
SiemensSCALANCE X200-4P IRTAll versions < V5.5.2Not stated
SiemensSCALANCE X201-3P IRTAll versions < V5.5.2Not stated
SiemensSCALANCE X201-3P IRT PROAll versions < V5.5.2Not stated
SiemensSCALANCE X202-2IRTAll versions < V5.5.2Not stated
SiemensSCALANCE X202-2P IRTAll versions < V5.5.2Not stated
SiemensSCALANCE X202-2P IRT PROAll versions < V5.5.2Not stated
SiemensSCALANCE X204-2All versions < V5.2.6Not stated
SiemensSCALANCE X204-2FMAll versions < V5.2.6Not stated
SiemensSCALANCE X204-2LDAll versions < V5.2.6Not stated
SiemensSCALANCE X204-2LD TSAll versions < V5.2.6Not stated
SiemensSCALANCE X204-2TSAll versions < V5.2.6Not stated
SiemensSCALANCE X204IRTAll versions < V5.5.2Not stated
SiemensSCALANCE X204IRT PROAll versions < V5.5.2Not stated
SiemensSCALANCE X206-1All versions < V5.2.6Not stated
SiemensSCALANCE X206-1LDAll versions < V5.2.6Not stated
SiemensSCALANCE X208All versions < V5.2.6Not stated
SiemensSCALANCE X208PROAll versions < V5.2.6Not stated
SiemensSCALANCE X212-2All versions < V5.2.6Not stated
SiemensSCALANCE X212-2LDAll versions < V5.2.6Not stated
SiemensSCALANCE X216All versions < V5.2.6Not stated
SiemensSCALANCE X224All versions < V5.2.6Not stated
SiemensSCALANCE XF201-3P IRTAll versions < V5.5.2Not stated
SiemensSCALANCE XF202-2P IRTAll versions < V5.5.2Not stated
SiemensSCALANCE XF204All versions < V5.2.6Not stated
SiemensSCALANCE XF204-2All versions < V5.2.6Not stated

Version data comes from the organisation that assigned the CVE; 33 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 systemScoreSeverityScored by
CVSS 3.18.8HighCNA (siemens.com)
CVSS 3.19.8CriticalNVD
CVSS 2.07.5HighNVD

Official description

A vulnerability has been identified in SCALANCE X200-4P IRT (All versions < V5.5.2), SCALANCE X201-3P IRT (All versions < V5.5.2), SCALANCE X201-3P IRT PRO (All versions < V5.5.2), SCALANCE X202-2IRT (All versions < V5.5.2), SCALANCE X202-2IRT (All versions < V5.5.2), SCALANCE X202-2P IRT (All versions < V5.5.2), SCALANCE X202-2P IRT PRO (All versions < V5.5.2), SCALANCE X204-2 (All versions < V5.2.6), SCALANCE X204-2FM (All versions < V5.2.6), SCALANCE X204-2LD (All versions < V5.2.6), SCALANCE X204-2LD TS (All versions < V5.2.6), SCALANCE X204-2TS (All versions < V5.2.6), SCALANCE X204IRT (All versions < V5.5.2), SCALANCE X204IRT (All versions < V5.5.2), SCALANCE X204IRT PRO (All versions < V5.5.2), SCALANCE X206-1 (All versions < V5.2.6), SCALANCE X206-1LD (All versions < V5.2.6), SCALANCE X208 (All versions < V5.2.6), SCALANCE X208PRO (All versions < V5.2.6), SCALANCE X212-2 (All versions < V5.2.6), SCALANCE X212-2LD (All versions < V5.2.6), SCALANCE X216 (All versions < V5.2.6), SCALANCE X224 (All versions < V5.2.6), SCALANCE XF201-3P IRT (All versions < V5.5.2), SCALANCE XF202-2P IRT (All versions < V5.5.2), SCALANCE XF204 (All versions < V5.2.6), SCALANCE XF204-2 (All versions < V5.2.6), SCALANCE XF204-2BA IRT (All versions < V5.5.2), SCALANCE XF204IRT (All versions < V5.5.2), SCALANCE XF206-1 (All versions < V5.2.6), SCALANCE XF208 (All versions < V5.2.6). The webserver of affected devices calculates session ids and nonces in an insecure manner. This could allow an unauthenticated remote attacker to brute-force session ids and hijack existing sessions.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use of Insufficiently Random Values

The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.

How developers prevent this class of flaw

  • Use a well-vetted algorithm that is currently considered to be strong by experts in the field, and select well-tested implementations with adequate length seeds. In general, if a pseudo-random number generator is not advertised as being cryptographically secure, then it is probably a statistical PRNG and should not be used in security-sensitive contexts. Pseudo-random number generators can produce predictable numbers if the generator is known and the seed can be guessed. A 256-bit seed is a good starting point for producing a random enough number.
  • Consider a PRNG that re-seeds itself as needed from high quality pseudo-random output sources, such as hardware devices.
  • Use products or modules that conform to FIPS 140-2 to avoid obvious entropy problems. Consult FIPS 140-2 Annex C (Approved Random Number Generators).

More Use of Insufficiently Random Values vulnerabilities (CWE-330)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in SCALANCE X200-4P IRT

All SCALANCE X200-4P IRT vulnerabilities

Recent Use of Insufficiently Random Values vulnerabilities

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