CyberSecBulletin
CVE-2023-26293NVD status: Modified

Totally Integrated Automation Portal (TIA…: Improper Limitation of a Pathname to a Restricted Directory

CVE-2023-26293 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in Totally Integrated Automation Portal (TIA Portal) V15 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 Totally Integrated Automation Portal (TIA Portal) V15 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 0.25% 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 Totally Integrated Automation Portal (TIA Portal) V16 to V16 Update 7 or a later version.
  2. Update Totally Integrated Automation Portal (TIA Portal) V17 to V17 Update 6 or a later version.
  3. Update Totally Integrated Automation Portal (TIA Portal) V18 to V18 Update 1 or a later version.
  4. Read the advisory on cert-portal.siemens.com for workarounds and exact fixed builds.
  5. 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
SiemensTotally Integrated Automation Portal (TIA Portal) V15all versionsNot stated
SiemensTotally Integrated Automation Portal (TIA Portal) V16before V16 Update 7V16 Update 7
SiemensTotally Integrated Automation Portal (TIA Portal) V17before V17 Update 6V17 Update 6
SiemensTotally Integrated Automation Portal (TIA Portal) V18before V18 Update 1V18 Update 1
SiemensTia Portal15; 16; 17; 18Not 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
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 NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.3HighCNA (siemens.com)
CVSS 3.17.8HighNVD

Official description

A vulnerability has been identified in Totally Integrated Automation Portal (TIA Portal) V15 (All versions), Totally Integrated Automation Portal (TIA Portal) V16 (All versions < V16 Update 7), Totally Integrated Automation Portal (TIA Portal) V17 (All versions < V17 Update 6), Totally Integrated Automation Portal (TIA Portal) V18 (All versions < V18 Update 1). Affected products contain a path traversal vulnerability that could allow the creation or overwrite of arbitrary files in the engineering system. If the user is tricked to open a malicious PC system configuration file, an attacker could exploit this vulnerability to achieve arbitrary code execution.

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

The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

How developers prevent this class of flaw

  • For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
  • 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.

More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)

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

Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities

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