CVE-2022-34821

A vulnerability has been identified in RUGGEDCOM RM1224 LTE(4G) EU (6GK6108-4AM00-2BA2), RUGGEDCOM RM1224 LTE(4G) NAM (6GK6108-4AM00-2DA2), SCALANCE M804PB (6GK5804-0AP00-2AA2), SCALANCE M812-1 ADSL-Router (6GK5812-1AA00-2AA2), SCALANCE M812-1 ADSL-Router (6GK5812-1BA00-2AA2), SCALANCE M816-1 ADSL-Router (6GK5816-1AA00-2AA2), SCALANCE M816-1 ADSL-Router (6GK5816-1BA00-2AA2), SCALANCE M826-2 SHDSL-Router (6GK5826-2AB00-2AB2), SCALANCE M874-2 (6GK5874-2AA00-2AA2), SCALANCE M874-3 (6GK5874-3AA00-2AA2), SCALANCE M876-3 (6GK5876-3AA02-2BA2), SCALANCE M876-3 (ROK) (6GK5876-3AA02-2EA2), SCALANCE M876-4 (6GK5876-4AA10-2BA2), SCALANCE M876-4 (EU) (6GK5876-4AA00-2BA2), SCALANCE M876-4 (NAM) (6GK5876-4AA00-2DA2), SCALANCE MUM853-1 (EU) (6GK5853-2EA00-2DA1), SCALANCE MUM856-1 (EU) (6GK5856-2EA00-3DA1), SCALANCE MUM856-1 (RoW) (6GK5856-2EA00-3AA1), SCALANCE S615 EEC LAN-Router (6GK5615-0AA01-2AA2), SCALANCE S615 LAN-Router (6GK5615-0AA00-2AA2), SCALANCE SC622-2C (6GK5622-2GS00-2AC2), SCALANCE SC622-2C (6GK5622-2GS00-2AC2), SCALANCE SC626-2C (6GK5626-2GS00-2AC2), SCALANCE SC626-2C (6GK5626-2GS00-2AC2), SCALANCE SC632-2C (6GK5632-2GS00-2AC2), SCALANCE SC632-2C (6GK5632-2GS00-2AC2), SCALANCE SC636-2C (6GK5636-2GS00-2AC2), SCALANCE SC636-2C (6GK5636-2GS00-2AC2), SCALANCE SC642-2C (6GK5642-2GS00-2AC2), SCALANCE SC642-2C (6GK5642-2GS00-2AC2), SCALANCE SC646-2C (6GK5646-2GS00-2AC2), SCALANCE SC646-2C (6GK5646-2GS00-2AC2), SCALANCE WAB762-1 (6GK5762-1AJ00-6AA0), SCALANCE WAM763-1 (6GK5763-1AL00-7DA0), SCALANCE WAM763-1 (ME) (6GK5763-1AL00-7DC0), SCALANCE WAM763-1 (US) (6GK5763-1AL00-7DB0), SCALANCE WAM766-1 (6GK5766-1GE00-7DA0), SCALANCE WAM766-1 (ME) (6GK5766-1GE00-7DC0), SCALANCE WAM766-1 (US) (6GK5766-1GE00-7DB0), SCALANCE WAM766-1 EEC (6GK5766-1GE00-7TA0), SCALANCE WAM766-1 EEC (ME) (6GK5766-1GE00-7TC0), SCALANCE WAM766-1 EEC (US) (6GK5766-1GE00-7TB0), SCALANCE WUB762-1 (6GK5762-1AJ00-1AA0), SCALANCE WUB762-1 iFeatures (6GK5762-1AJ00-2AA0), SCALANCE WUM763-1 (6GK5763-1AL00-3AA0), SCALANCE WUM763-1 (6GK5763-1AL00-3DA0), SCALANCE WUM763-1 (US) (6GK5763-1AL00-3AB0), SCALANCE WUM763-1 (US) (6GK5763-1AL00-3DB0), SCALANCE WUM766-1 (6GK5766-1GE00-3DA0), SCALANCE WUM766-1 (ME) (6GK5766-1GE00-3DC0), SCALANCE WUM766-1 (USA) (6GK5766-1GE00-3DB0), SIMATIC CP 1242-7 V2 (6GK7242-7KX31-0XE0), SIMATIC CP 1243-1 (6GK7243-1BX30-0XE0), SIMATIC CP 1243-7 LTE EU (6GK7243-7KX30-0XE0), SIMATIC CP 1243-7 LTE US (6GK7243-7SX30-0XE0), SIMATIC CP 1243-8 IRC (6GK7243-8RX30-0XE0), SIMATIC CP 1542SP-1 IRC (6GK7542-6VX00-0XE0), SIMATIC CP 1543-1 (6GK7543-1AX00-0XE0), SIMATIC CP 1543SP-1 (6GK7543-6WX00-0XE0), SIPLUS ET 200SP CP 1542SP-1 IRC TX RAIL (6AG2542-6VX00-4XE0), SIPLUS ET 200SP CP 1543SP-1 ISEC (6AG1543-6WX00-7XE0), SIPLUS ET 200SP CP 1543SP-1 ISEC TX RAIL (6AG2543-6WX00-4XE0), SIPLUS NET CP 1242-7 V2 (6AG1242-7KX31-7XE0), SIPLUS NET CP 1543-1 (6AG1543-1AX00-2XE0), SIPLUS S7-1200 CP 1243-1 (6AG1243-1BX30-2AX0), SIPLUS S7-1200 CP 1243-1 RAIL (6AG2243-1BX30-1XE0). By injecting code to specific configuration options for OpenVPN, an attacker could execute arbitrary code with elevated privileges.

Weakness

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

Affected Software

Extended Description

When a product allows a user’s input to contain code syntax, it might be possible for an attacker to craft the code in such a way that it will alter the intended control flow of the product. Such an alteration could lead to arbitrary code execution. Injection problems encompass a wide variety of issues – all mitigated in very different ways. For this reason, the most effective way to discuss these weaknesses is to note the distinct features which classify them as injection weaknesses. The most important issue to note is that all injection problems share one thing in common – i.e., they allow for the injection of control plane data into the user-controlled data plane. This means that the execution of the process may be altered by sending code in through legitimate data channels, using no other mechanism. While buffer overflows, and many other flaws, involve the use of some further issue to gain execution, injection problems need only for the data to be parsed. The most classic instantiations of this category of weakness are SQL injection and format string vulnerabilities.

Potential Mitigations

• Run your code in a “jail” or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product.
• Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection.
• This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise.
• Be careful to avoid CWE-243 and other weaknesses related to jails.
• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of code injection, use stringent allowlists that limit which constructs are allowed. If you are dynamically constructing code that invokes a function, then verifying that the input is alphanumeric might be insufficient. An attacker might still be able to reference a dangerous function that you did not intend to allow, such as system(), exec(), or exit().

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/242.html
• https://cwe.mitre.org/data/definitions/35.html
• https://cwe.mitre.org/data/definitions/77.html

References

• https://cert-portal.siemens.com/productcert/html/ssa-413565.html
• https://cert-portal.siemens.com/productcert/html/ssa-517377.html
• https://cert-portal.siemens.com/productcert/pdf/ssa-413565.pdf
• https://cert-portal.siemens.com/productcert/pdf/ssa-517377.pdf
• https://cert-portal.siemens.com/productcert/pdf/ssa-413565.pdf
• https://cert-portal.siemens.com/productcert/pdf/ssa-517377.pdf