CVE-2024-50591

An attacker with local access the to medical office computer can escalate his Windows user privileges to NT AUTHORITYSYSTEM by exploiting a command injection vulnerability in the Elefant Update Service. The command injection can be exploited by communicating with the Elefant Update Service which is running as SYSTEM via Windows Named Pipes.The Elefant Software Updater (ESU) consists of two components. An ESU service which runs as NT AUTHORITYSYSTEM and an ESU tray client which communicates with the service to update or repair the installation and is running with user permissions. The communication is implemented using named pipes. A crafted message of type MessageType.SupportServiceInfos can be sent to the local ESU service to inject commands, which are then executed as NT AUTHORITYSYSTEM.

Weakness

The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

Extended Description

Command injection vulnerabilities typically occur when:

Many protocols and products have their own custom command language. While OS or shell command strings are frequently discovered and targeted, developers may not realize that these other command languages might also be vulnerable to attacks. Command injection is a common problem with wrapper programs.

Potential Mitigations

• 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.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/136.html
• https://cwe.mitre.org/data/definitions/15.html
• https://cwe.mitre.org/data/definitions/183.html
• https://cwe.mitre.org/data/definitions/248.html
• https://cwe.mitre.org/data/definitions/40.html
• https://cwe.mitre.org/data/definitions/43.html
• https://cwe.mitre.org/data/definitions/75.html
• https://cwe.mitre.org/data/definitions/76.html

References

• https://hasomed.de/produkte/elefant/
• https://r.sec-consult.com/hasomed