CyberSecBulletin
CVE-2024-49849NVD status: Deferred

SIMATIC S7-PLCSIM V16: Deserialization of Untrusted Data

Published Updated By the CyberSecBulletin desk

CVE-2024-49849 is a high-severity deserialization of untrusted data vulnerability in SIMATIC S7-PLCSIM V16 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. Affected SIMATIC S7-PLCSIM V16 versions: all versions. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.22% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update SIMATIC STEP 7 Safety V17 to V17 Update 9 or a later version.
  2. Update SIMATIC STEP 7 Safety V18 to V18 Update 6 or a later version.
  3. Update SIMATIC STEP 7 Safety V19 to V19 Update 4 or a later version.
  4. 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

VendorProductAffected versionsFixed in
SiemensSIMATIC S7-PLCSIM V16all versionsNot stated
SiemensSIMATIC S7-PLCSIM V17all versionsNot stated
SiemensSIMATIC STEP 7 Safety V16all versionsNot stated
SiemensSIMATIC STEP 7 Safety V17before V17 Update 9V17 Update 9
SiemensSIMATIC STEP 7 Safety V18before V18 Update 6V18 Update 6
SiemensSIMATIC STEP 7 Safety V19before V19 Update 4V19 Update 4
SiemensSIMATIC STEP 7 V16all versionsNot stated
SiemensSIMATIC STEP 7 V17before V17 Update 9V17 Update 9
SiemensSIMATIC STEP 7 V18before V18 Update 6V18 Update 6
SiemensSIMATIC STEP 7 V19before V19 Update 4V19 Update 4
SiemensSIMATIC WinCC Unified V16all versionsNot stated
SiemensSIMATIC WinCC Unified V17before V17 Update 9V17 Update 9
SiemensSIMATIC WinCC Unified V18before V18 Update 6V18 Update 6
SiemensSIMATIC WinCC Unified V19before V19 Update 4V19 Update 4
SiemensSIMATIC WinCC V16all versionsNot stated
SiemensSIMATIC WinCC V17before V17 Update 9V17 Update 9
SiemensSIMATIC WinCC V18before V18 Update 6V18 Update 6
SiemensSIMATIC WinCC V19before V19 Update 4V19 Update 4
SiemensSIMOCODE ES V16all versionsNot stated
SiemensSIMOCODE ES V17all versionsNot stated
SiemensSIMOCODE ES V18all versionsNot stated
SiemensSIMOCODE ES V19all versionsNot stated
SiemensSIMOTION SCOUT TIA V5.4before V17 Update 9V17 Update 9
SiemensSIMOTION SCOUT TIA V5.5before V18 Update 6V18 Update 6
SiemensSIMOTION SCOUT TIA V5.6before V19 Update 4V19 Update 4

Version data comes from the organisation that assigned the CVE; 14 further products are omitted here. 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 systemScoreSeverityScored by
CVSS 4.08.4HighCNA (siemens.com)
CVSS 3.17.8HighCNA (siemens.com)

Official description

A vulnerability has been identified in SIMATIC S7-PLCSIM V16 (All versions), SIMATIC S7-PLCSIM V17 (All versions), SIMATIC STEP 7 Safety V16 (All versions), SIMATIC STEP 7 Safety V17 (All versions < V17 Update 9), SIMATIC STEP 7 Safety V18 (All versions < V18 Update 6), SIMATIC STEP 7 Safety V19 (All versions < V19 Update 4), SIMATIC STEP 7 V16 (All versions), SIMATIC STEP 7 V17 (All versions < V17 Update 9), SIMATIC STEP 7 V18 (All versions < V18 Update 6), SIMATIC STEP 7 V19 (All versions < V19 Update 4), SIMATIC WinCC Unified V16 (All versions), SIMATIC WinCC Unified V17 (All versions < V17 Update 9), SIMATIC WinCC Unified V18 (All versions < V18 Update 6), SIMATIC WinCC Unified V19 (All versions < V19 Update 4), SIMATIC WinCC V16 (All versions), SIMATIC WinCC V17 (All versions < V17 Update 9), SIMATIC WinCC V18 (All versions < V18 Update 6), SIMATIC WinCC V19 (All versions < V19 Update 4), SIMOCODE ES V16 (All versions), SIMOCODE ES V17 (All versions), SIMOCODE ES V18 (All versions), SIMOCODE ES V19 (All versions), SIMOTION SCOUT TIA V5.4 (All versions < V17 Update 9), SIMOTION SCOUT TIA V5.5 (All versions < V18 Update 6), SIMOTION SCOUT TIA V5.6 (All versions < V19 Update 4), SINAMICS Startdrive V16 (All versions), SINAMICS Startdrive V17 (All versions), SINAMICS Startdrive V18 (All versions), SINAMICS Startdrive V19 (All versions), SIRIUS Safety ES V17 (TIA Portal) (All versions), SIRIUS Safety ES V18 (TIA Portal) (All versions < V18 Update 6), SIRIUS Safety ES V19 (TIA Portal) (All versions), SIRIUS Soft Starter ES V17 (TIA Portal) (All versions), SIRIUS Soft Starter ES V18 (TIA Portal) (All versions), SIRIUS Soft Starter ES V19 (TIA Portal) (All versions), TIA Portal Cloud V16 (All versions), TIA Portal Cloud V17 (All versions < V6.0.0.0), TIA Portal Cloud V18 (All versions < V6.3.0.2), TIA Portal Cloud V19 (All versions < V5.2.1.1). Affected products do not properly sanitize user-controllable input when parsing log files. This could allow an attacker to cause a type confusion and execute arbitrary code within the affected application.

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

The underlying weakness: Deserialization of Untrusted Data

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

How developers prevent this class of flaw

  • If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
  • When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
  • Explicitly define a final object() to prevent deserialization.

More Deserialization of Untrusted Data vulnerabilities (CWE-502)

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 SIMATIC S7-PLCSIM V16

All SIMATIC S7-PLCSIM V16 vulnerabilities

Recent Deserialization of Untrusted Data vulnerabilities

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