Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
CWE-15 Base Incomplete
External Control of System or Configuration Setting
This vulnerability occurs when an application allows users to directly modify critical system settings or configuration values from an external source.
Definition
What is CWE-15?
This vulnerability occurs when an application allows users to directly modify critical system settings or configuration values from an external source.
When system settings like file paths, feature flags, or environment variables can be controlled by an external user, it breaks the fundamental trust between the application and its configuration. Attackers can exploit this to disrupt services, bypass security controls, or force the application to execute unintended and potentially malicious actions, leading to data loss or system compromise.
Preventing this requires rigorous validation of all configuration inputs and enforcing strict separation between user data and system controls. While SAST tools can catch the pattern, Plexicus uses AI to analyze the data flow and suggest the precise code fix—such as implementing allowlists or moving configurations to secure, internal sources—saving hours of manual remediation work across your codebase.
Auswirkungen in der Praxis
Real-world CVEs caused by CWE-15
Bisher sind in MITREs Katalog keine öffentlichen CVE-Referenzen mit dieser CWE verknüpft.
Wie Angreifer es ausnutzen
Angreiferpfad Schritt für Schritt
- 1
The following C code accepts a number as one of its command line parameters and sets it as the host ID of the current machine.
- 2
Although a process must be privileged to successfully invoke sethostid(), unprivileged users may be able to invoke the program. The code in this example allows user input to directly control the value of a system setting. If an attacker provides a malicious value for host ID, the attacker can misidentify the affected machine on the network or cause other unintended behavior.
- 3
The following Java code snippet reads a string from an HttpServletRequest and sets it as the active catalog for a database Connection.
- 4
In this example, an attacker could cause an error by providing a nonexistent catalog name or connect to an unauthorized portion of the database.
Verwundbares Codebeispiel
Vulnerable C
The following C code accepts a number as one of its command line parameters and sets it as the host ID of the current machine.
...
sethostid(argv[1]);
... Sicheres Codebeispiel
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.
Präventions-Checkliste
How to prevent CWE-15
- Architecture and Design Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
- Implementation / Architecture and Design Because setting manipulation covers a diverse set of functions, any attempt at illustrating it will inevitably be incomplete. Rather than searching for a tight-knit relationship between the functions addressed in the setting manipulation category, take a step back and consider the sorts of system values that an attacker should not be allowed to control.
- Implementation / Architecture and Design In general, do not allow user-provided or otherwise untrusted data to control sensitive values. The leverage that an attacker gains by controlling these values is not always immediately obvious, but do not underestimate the creativity of the attacker.
Erkennungssignale
How to detect CWE-15
CWE-15
Don't catalog this weakness. Prove it's reachable.
Plexicus turns CWE catalogs into evidence: every CWE-pattern is matched against your real code graph, reach is proven on a sandbox clone, and verified findings ship as reviewed PRs.
Häufig gestellte Fragen Was ist CWE-15?
Wie gravierend ist CWE-15?
Welche Sprachen oder Plattformen sind von CWE-15 betroffen?
Wie kann ich CWE-15 verhindern?
Wie erkennt und behebt Plexicus CWE-15?
Wo erfahre ich mehr über CWE-15?
Frequently asked questions
Was ist CWE-15?
This vulnerability occurs when an application allows users to directly modify critical system settings or configuration values from an external source.
Wie gravierend ist CWE-15?
MITRE hat für diese Schwachstelle keine Exploit-Wahrscheinlichkeit veröffentlicht. Behandle sie als mittlere Auswirkung, bis dein Threat Model anderes belegt.
Welche Sprachen oder Plattformen sind von CWE-15 betroffen?
MITRE lists the following affected platforms: Not Technology-Specific, ICS/OT.
Wie kann ich CWE-15 verhindern?
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to…
Wie erkennt und behebt Plexicus CWE-15?
Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-15 bei jedem Commit. Bei einem Treffer öffnet unser Codex-Remedium-Agent einen Fix-PR mit korrigiertem Code, Tests und einer einzeiligen Zusammenfassung für den Reviewer.
Wo erfahre ich mehr über CWE-15?
MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/15.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.
Verwandte Schwachstellen
Weaknesses related to CWE-15
CWE-642 Parent
External Control of Critical State Data
This vulnerability occurs when an application stores security-sensitive state data in locations that unauthorized users can access and…
CWE-426 Sibling
Untrusted Search Path
This vulnerability occurs when an application relies on an external search path, provided by a user or environment, to find and load…
CWE-472 Sibling
External Control of Assumed-Immutable Web Parameter
This vulnerability occurs when a web application incorrectly trusts data that appears to be fixed or hidden from the user, such as values…
CWE-565 Sibling
Reliance on Cookies without Validation and Integrity Checking
This vulnerability occurs when an application uses cookies to make security decisions—like granting access or changing settings—but fails…
CWE-73 Sibling
External Control of File Name or Path
This vulnerability occurs when an application uses unvalidated user input to construct file or directory paths for filesystem operations.
Ressourcen
Further reading
- MITRE — offizielle CWE-15 https://cwe.mitre.org/data/definitions/15.html
- Seven Pernicious Kingdoms: A Taxonomy of Software Security Errors https://samate.nist.gov/SSATTM_Content/papers/Seven%20Pernicious%20Kingdoms%20-%20Taxonomy%20of%20Sw%20Security%20Errors%20-%20Tsipenyuk%20-%20Chess%20-%20McGraw.pdf
Bereit, das Wesentliche zu validieren?
Bereit zu validieren, was zählt.
Plexicus ist Proof-Driven AppSec: validierte Funde, kontextuelles Verständnis und geprüfte Remediation — in Evidenz verankert, mit Ihnen gescoped.