CVE-2022-40181

A vulnerability has been identified in Desigo PXM30-1 (All versions < V02.20.126.11-41), Desigo PXM30.E (All versions < V02.20.126.11-41), Desigo PXM40-1 (All versions < V02.20.126.11-41), Desigo PXM40.E (All versions < V02.20.126.11-41), Desigo PXM50-1 (All versions < V02.20.126.11-41), Desigo PXM50.E (All versions < V02.20.126.11-41), PXG3.W100-1 (All versions < V02.20.126.11-37), PXG3.W100-2 (All versions < V02.20.126.11-41), PXG3.W200-1 (All versions < V02.20.126.11-37), PXG3.W200-2 (All versions < V02.20.126.11-41). The device embedded browser does not prevent interaction with alternative URI schemes when redirected to corresponding resources by web application code. By setting the homepage URI, the favorite URIs, or redirecting embedded browser users via JavaScript code to alternative scheme resources, a remote low privileged attacker can perform a range of attacks against the device, such as read arbitrary files on the filesystem, execute arbitrary JavaScript code in order to steal or manipulate the information on the screen, or trigger denial of service conditions.

Weakness

The web application improperly neutralizes user-controlled input for executable script disguised with URI encodings.

Affected Software

Potential Mitigations

• Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.
• The problem of inconsistent output encodings often arises in web pages. If an encoding is not specified in an HTTP header, web browsers often guess about which encoding is being used. This can open up the browser to subtle XSS attacks.

References

• https://cert-portal.siemens.com/productcert/pdf/ssa-360783.pdf
• https://cert-portal.siemens.com/productcert/pdf/ssa-360783.pdf