CVE-2021-42020

A vulnerability has been identified in RUGGEDCOM i800, RUGGEDCOM i800NC, RUGGEDCOM i801, RUGGEDCOM i801NC, RUGGEDCOM i802, RUGGEDCOM i802NC, RUGGEDCOM i803, RUGGEDCOM i803NC, RUGGEDCOM M2100, RUGGEDCOM M2100NC, RUGGEDCOM M2200, RUGGEDCOM M2200NC, RUGGEDCOM M969, RUGGEDCOM M969NC, RUGGEDCOM RMC30, RUGGEDCOM RMC30NC, RUGGEDCOM RMC8388 V4.X, RUGGEDCOM RMC8388 V5.X, RUGGEDCOM RMC8388NC V4.X, RUGGEDCOM RMC8388NC V5.X, RUGGEDCOM RP110, RUGGEDCOM RP110NC, RUGGEDCOM RS1600, RUGGEDCOM RS1600F, RUGGEDCOM RS1600FNC, RUGGEDCOM RS1600NC, RUGGEDCOM RS1600T, RUGGEDCOM RS1600TNC, RUGGEDCOM RS400, RUGGEDCOM RS400NC, RUGGEDCOM RS401, RUGGEDCOM RS401NC, RUGGEDCOM RS416, RUGGEDCOM RS416NC, RUGGEDCOM RS416NCv2 V4.X, RUGGEDCOM RS416NCv2 V5.X, RUGGEDCOM RS416P, RUGGEDCOM RS416PNC, RUGGEDCOM RS416PNCv2 V4.X, RUGGEDCOM RS416PNCv2 V5.X, RUGGEDCOM RS416Pv2 V4.X, RUGGEDCOM RS416Pv2 V5.X, RUGGEDCOM RS416v2 V4.X, RUGGEDCOM RS416v2 V5.X, RUGGEDCOM RS8000, RUGGEDCOM RS8000A, RUGGEDCOM RS8000ANC, RUGGEDCOM RS8000H, RUGGEDCOM RS8000HNC, RUGGEDCOM RS8000NC, RUGGEDCOM RS8000T, RUGGEDCOM RS8000TNC, RUGGEDCOM RS900, RUGGEDCOM RS900 (32M) V4.X, RUGGEDCOM RS900 (32M) V5.X, RUGGEDCOM RS900G, RUGGEDCOM RS900G (32M) V4.X, RUGGEDCOM RS900G (32M) V5.X, RUGGEDCOM RS900GNC, RUGGEDCOM RS900GNC(32M) V4.X, RUGGEDCOM RS900GNC(32M) V5.X, RUGGEDCOM RS900GP, RUGGEDCOM RS900GPNC, RUGGEDCOM RS900L, RUGGEDCOM RS900LNC, RUGGEDCOM RS900M-GETS-C01, RUGGEDCOM RS900M-GETS-XX, RUGGEDCOM RS900M-STND-C01, RUGGEDCOM RS900M-STND-XX, RUGGEDCOM RS900MNC-GETS-C01, RUGGEDCOM RS900MNC-GETS-XX, RUGGEDCOM RS900MNC-STND-XX, RUGGEDCOM RS900MNC-STND-XX-C01, RUGGEDCOM RS900NC, RUGGEDCOM RS900NC(32M) V4.X, RUGGEDCOM RS900NC(32M) V5.X, RUGGEDCOM RS900W, RUGGEDCOM RS910, RUGGEDCOM RS910L, RUGGEDCOM RS910LNC, RUGGEDCOM RS910NC, RUGGEDCOM RS910W, RUGGEDCOM RS920L, RUGGEDCOM RS920LNC, RUGGEDCOM RS920W, RUGGEDCOM RS930L, RUGGEDCOM RS930LNC, RUGGEDCOM RS930W, RUGGEDCOM RS940G, RUGGEDCOM RS940GNC, RUGGEDCOM RS969, RUGGEDCOM RS969NC, RUGGEDCOM RSG2100, RUGGEDCOM RSG2100 (32M) V4.X, RUGGEDCOM RSG2100 (32M) V5.X, RUGGEDCOM RSG2100NC, RUGGEDCOM RSG2100NC(32M) V4.X, RUGGEDCOM RSG2100NC(32M) V5.X, RUGGEDCOM RSG2100P, RUGGEDCOM RSG2100PNC, RUGGEDCOM RSG2200, RUGGEDCOM RSG2200NC, RUGGEDCOM RSG2288 V4.X, RUGGEDCOM RSG2288 V5.X, RUGGEDCOM RSG2288NC V4.X, RUGGEDCOM RSG2288NC V5.X, RUGGEDCOM RSG2300 V4.X, RUGGEDCOM RSG2300 V5.X, RUGGEDCOM RSG2300NC V4.X, RUGGEDCOM RSG2300NC V5.X, RUGGEDCOM RSG2300P V4.X, RUGGEDCOM RSG2300P V5.X, RUGGEDCOM RSG2300PNC V4.X, RUGGEDCOM RSG2300PNC V5.X, RUGGEDCOM RSG2488 V4.X, RUGGEDCOM RSG2488 V5.X, RUGGEDCOM RSG2488NC V4.X, RUGGEDCOM RSG2488NC V5.X, RUGGEDCOM RSG907R, RUGGEDCOM RSG908C, RUGGEDCOM RSG909R, RUGGEDCOM RSG910C, RUGGEDCOM RSG920P V4.X, RUGGEDCOM RSG920P V5.X, RUGGEDCOM RSG920PNC V4.X, RUGGEDCOM RSG920PNC V5.X, RUGGEDCOM RSL910, RUGGEDCOM RSL910NC, RUGGEDCOM RST2228, RUGGEDCOM RST2228P, RUGGEDCOM RST916C, RUGGEDCOM RST916P. The third-party component, in its TFTP functionality fails to check for null terminations in file names.

If an attacker were to exploit this, it could result in data corruption, and possibly a hard-fault of the application.

Weakness

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

Affected Software

Extended Description

The programmer may assume that certain events or conditions will never occur or do not need to be worried about, such as low memory conditions, lack of access to resources due to restrictive permissions, or misbehaving clients or components. However, attackers may intentionally trigger these unusual conditions, thus violating the programmer’s assumptions, possibly introducing instability, incorrect behavior, or a vulnerability. Note that this entry is not exclusively about the use of exceptions and exception handling, which are mechanisms for both checking and handling unusual or unexpected conditions.

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• Choose languages with features such as exception handling that force the programmer to anticipate unusual conditions that may generate exceptions. Custom exceptions may need to be developed to handle unusual business-logic conditions. Be careful not to pass sensitive exceptions back to the user (CWE-209, CWE-248).
• Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success.
• If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files.
• Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.
• Exposing additional information to a potential attacker in the context of an exceptional condition can help the attacker determine what attack vectors are most likely to succeed beyond DoS.
• 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.

References

• https://cert-portal.siemens.com/productcert/pdf/ssa-256353.pdf