CWE-657 Class Draft

Violation of Secure Design Principles

This weakness occurs when a system's architecture or design fails to follow fundamental security principles, creating a flawed foundation that can lead to multiple vulnerabilities.

Definition

What is CWE-657?

This weakness occurs when a system's architecture or design fails to follow fundamental security principles, creating a flawed foundation that can lead to multiple vulnerabilities.
A design that ignores secure principles, like least privilege or defense in depth, acts as a blueprint for insecurity. It often introduces specific security flaws directly and makes it easier for developers to accidentally create related bugs during coding, as they are building on an inherently weak structure. Fixing these foundational design problems is typically costly and complex because the insecure assumptions are woven throughout the entire codebase. Addressing them may require significant architectural changes, unlike patching a single coding error, which makes prevention through secure design reviews critical early in the development lifecycle.
Real-world impact

Real-world CVEs caused by CWE-657

  • CVE-2019-6260

    Baseboard Management Controller (BMC) device implements Advanced High-performance Bus (AHB) bridges that do not require authentication for arbitrary read and write access to the BMC's physical address space from the host, and possibly the network [REF-1138].

  • CVE-2007-5277

    The failure of connection attempts in a web browser resets DNS pin restrictions. An attacker can then bypass the same origin policy by rebinding a domain name to a different IP address. This was an attempt to "fail functional."

  • CVE-2006-7142

    Hard-coded cryptographic key stored in executable program.

  • CVE-2007-0408

    Server does not properly validate client certificates when reusing cached connections.

How attackers exploit it

Step-by-step attacker path

  1. 1

    Switches may revert their functionality to that of hubs when the table used to map ARP information to the switch interface overflows, such as when under a spoofing attack. This results in traffic being broadcast to an eavesdropper, instead of being sent only on the relevant switch interface. To mitigate this type of problem, the developer could limit the number of ARP entries that can be recorded for a given switch interface, while other interfaces may keep functioning normally. Configuration options can be provided on the appropriate actions to be taken in case of a detected failure, but safe defaults should be used.

  2. 2

    The IPSEC specification is complex, which resulted in bugs, partial implementations, and incompatibilities between vendors.

  3. 3

    When executable library files are used on web servers, which is common in PHP applications, the developer might perform an access check in any user-facing executable, and omit the access check from the library file itself. By directly requesting the library file (CWE-425), an attacker can bypass this access check.

  4. 4

    Single sign-on technology is intended to make it easier for users to access multiple resources or domains without having to authenticate each time. While this is highly convenient for the user and attempts to address problems with psychological acceptability, it also means that a compromise of a user's credentials can provide immediate access to all other resources or domains.

  5. 5

    The design of TCP relies on the secrecy of Initial Sequence Numbers (ISNs), as originally covered in CVE-1999-0077 [REF-542]. If ISNs can be guessed (due to predictability, CWE-330) or sniffed (due to lack of encryption during transmission, CWE-312), then an attacker can hijack or spoof connections. Many TCP implementations have had variations of this problem over the years, including CVE-2004-0641, CVE-2002-1463, CVE-2001-0751, CVE-2001-0328, CVE-2001-0288, CVE-2001-0163, CVE-2001-0162, CVE-2000-0916, and CVE-2000-0328.

Vulnerable code example

Vulnerable pseudo

MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.

Vulnerable pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
Secure code example

Secure pseudo

Secure pseudo 
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}
What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist

How to prevent CWE-657

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Detection signals

How to detect CWE-657

SAST High

Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.

DAST Moderate

Run dynamic application security testing against the live endpoint.

Runtime Moderate

Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.

Code review Moderate

Code review: flag any new code that handles input from this surface without using the validated framework helpers.

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Frequently asked questions

Frequently asked questions

What is CWE-657?

This weakness occurs when a system's architecture or design fails to follow fundamental security principles, creating a flawed foundation that can lead to multiple vulnerabilities.

How serious is CWE-657?

MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.

What languages or platforms are affected by CWE-657?

MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.

How can I prevent CWE-657?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

How does Plexicus detect and fix CWE-657?

Plexicus's SAST engine matches the data-flow signature for CWE-657 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.

Where can I learn more about CWE-657?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/657.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-657

CWE-710 Parent

Improper Adherence to Coding Standards

This weakness occurs when developers don't consistently follow established coding standards and best practices, which can introduce…

CWE-1041 Sibling

Use of Redundant Code

This weakness occurs when a codebase contains identical or nearly identical logic duplicated across multiple functions, methods, or…

CWE-1044 Sibling

Architecture with Number of Horizontal Layers Outside of Expected Range

This occurs when a software system is built with either too many or too few distinct architectural layers, falling outside a recommended…

CWE-1048 Sibling

Invokable Control Element with Large Number of Outward Calls

This weakness occurs when a single function, method, or callable code block makes an excessively high number of calls to other objects or…

CWE-1059 Sibling

Insufficient Technical Documentation

This weakness occurs when a software or hardware product lacks comprehensive technical documentation. Missing or incomplete details about…

CWE-1061 Sibling

Insufficient Encapsulation

This weakness occurs when a software component exposes too much of its internal workings, such as data structures or implementation logic.…

CWE-1065 Sibling

Runtime Resource Management Control Element in a Component Built to Run on Application Servers

This weakness occurs when an application built to run on a managed application server bypasses the server's high-level APIs and instead…

CWE-1066 Sibling

Missing Serialization Control Element

This weakness occurs when a class or data structure is marked as serializable but lacks the required control methods to properly handle…

CWE-1068 Sibling

Inconsistency Between Implementation and Documented Design

This weakness occurs when the actual code implementation deviates from the intended design described in its official documentation,…

Resources

Further reading

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