CWE-259 Variant Draft High likelihood

Use of Hard-coded Password

This vulnerability occurs when an application embeds a password directly into its source code or configuration files. This hard-coded secret is then used either to authenticate incoming users or to…

Definition

What is CWE-259?

This vulnerability occurs when an application embeds a password directly into its source code or configuration files. This hard-coded secret is then used either to authenticate incoming users or to connect to external services and databases.
Hard-coded passwords create two major security risks. First, for inbound authentication, anyone with access to the code can discover the password and gain unauthorized access. Second, for outbound connections, the embedded credentials for databases, APIs, or other services cannot be changed without modifying and redeploying the application, making rotation and management nearly impossible. Both scenarios bypass standard secret management and leave the system permanently exposed if the code is ever leaked or shared. To fix this, always store passwords, API keys, and other secrets in secure, external management systems like environment variables, vaults, or dedicated secret managers. This allows for secure access control, auditing, and easy rotation without code changes. While SAST tools can detect the hard-coded pattern, Plexicus uses AI to analyze the context and suggest the correct remediation—such as replacing the static string with a secure fetch from a vault—saving developers hours of manual refactoring and reducing the risk of misconfiguration.
Vulnerability Diagram CWE-259
Hard-coded Password auth.py (in repo) def login(user, pw): if pw == "admin123": return True # backdoor return check_db(user, pw) Anyone w/ source / binary strings binary | grep admin → "admin123" login as admin on every install Compiled binaries still leak the literal — secrets must come from config/secrets store.
Auswirkungen in der Praxis

Real-world CVEs caused by CWE-259

  • Distributed Control System (DCS) has hard-coded passwords for local shell access

  • Telnet service for IoT feeder for dogs and cats has hard-coded password [REF-1288]

  • Firmware for a WiFi router uses a hard-coded password for a BusyBox shell, allowing bypass of authentication through the UART port

Wie Angreifer es ausnutzen

Angreiferpfad Schritt für Schritt

  1. 1

    The following code uses a hard-coded password to connect to a database:

  2. 2

    This is an example of an external hard-coded password on the client-side of a connection. This code will run successfully, but anyone who has access to it will have access to the password. Once the program has shipped, there is no going back from the database user "scott" with a password of "tiger" unless the program is patched. A devious employee with access to this information can use it to break into the system. Even worse, if attackers have access to the bytecode for application, they can use the javap -c command to access the disassembled code, which will contain the values of the passwords used. The result of this operation might look something like the following for the example above:

  3. 3

    The following code is an example of an internal hard-coded password in the back-end:

  4. 4

    Every instance of this program can be placed into diagnostic mode with the same password. Even worse is the fact that if this program is distributed as a binary-only distribution, it is very difficult to change that password or disable this "functionality."

  5. 5

    The following examples show a portion of properties and configuration files for Java and ASP.NET applications. The files include username and password information but they are stored in cleartext.

Verwundbares Codebeispiel

Vulnerable Java

The following code uses a hard-coded password to connect to a database:

Verwundbar Java
...
  DriverManager.getConnection(url, "scott", "tiger");
  ...
Angreifer-Payload

This is an example of an external hard-coded password on the client-side of a connection. This code will run successfully, but anyone who has access to it will have access to the password. Once the program has shipped, there is no going back from the database user "scott" with a password of "tiger" unless the program is patched. A devious employee with access to this information can use it to break into the system. Even worse, if attackers have access to the bytecode for application, they can use the javap -c command to access the disassembled code, which will contain the values of the passwords used. The result of this operation might look something like the following for the example above:

Angreifer-Payload
javap -c ConnMngr.class
  	22: ldc #36; //String jdbc:mysql://ixne.com/rxsql
  	24: ldc #38; //String scott
  	26: ldc #17; //String tiger
Sicheres Codebeispiel

Secure pseudo

Sicher 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-259

  • Architecture and Design For outbound authentication: store passwords outside of the code in a strongly-protected, encrypted configuration file or database that is protected from access by all outsiders, including other local users on the same system. Properly protect the key (CWE-320). If you cannot use encryption to protect the file, then make sure that the permissions are as restrictive as possible.
  • Architecture and Design For inbound authentication: Rather than hard-code a default username and password for first time logins, utilize a "first login" mode that requires the user to enter a unique strong password.
  • Architecture and Design Perform access control checks and limit which entities can access the feature that requires the hard-coded password. For example, a feature might only be enabled through the system console instead of through a network connection.
  • Architecture and Design For inbound authentication: apply strong one-way hashes to your passwords and store those hashes in a configuration file or database with appropriate access control. That way, theft of the file/database still requires the attacker to try to crack the password. When receiving an incoming password during authentication, take the hash of the password and compare it to the hash that you have saved. Use randomly assigned salts for each separate hash that you generate. This increases the amount of computation that an attacker needs to conduct a brute-force attack, possibly limiting the effectiveness of the rainbow table method.
  • Architecture and Design For front-end to back-end connections: Three solutions are possible, although none are complete. ``` The first suggestion involves the use of generated passwords which are changed automatically and must be entered at given time intervals by a system administrator. These passwords will be held in memory and only be valid for the time intervals. Next, the passwords used should be limited at the back end to only performing actions valid for the front end, as opposed to having full access. Finally, the messages sent should be tagged and checksummed with time sensitive values so as to prevent replay style attacks. ```
Erkennungssignale

How to detect CWE-259

Manual Analysis

This weakness can be detected using tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session.

Black Box

Use monitoring tools that examine the software's process as it interacts with the operating system and the network. This technique is useful in cases when source code is unavailable, if the software was not developed by you, or if you want to verify that the build phase did not introduce any new weaknesses. Examples include debuggers that directly attach to the running process; system-call tracing utilities such as truss (Solaris) and strace (Linux); system activity monitors such as FileMon, RegMon, Process Monitor, and other Sysinternals utilities (Windows); and sniffers and protocol analyzers that monitor network traffic. Attach the monitor to the process and perform a login. Using disassembled code, look at the associated instructions and see if any of them appear to be comparing the input to a fixed string or value.

Automated Static Analysis High

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.)

Plexicus Auto-Fix

Plexicus erkennt CWE-259 automatisch und öffnet in unter 60 Sekunden einen Fix-PR.

Codex Remedium scannt jeden Commit, identifiziert genau diese Schwachstelle und liefert einen reviewer-ready Pull Request mit dem Patch. Keine Tickets. Keine Hand-offs.

Häufig gestellte Fragen

Frequently asked questions

Was ist CWE-259?

This vulnerability occurs when an application embeds a password directly into its source code or configuration files. This hard-coded secret is then used either to authenticate incoming users or to connect to external services and databases.

Wie gravierend ist CWE-259?

MITRE stuft die Exploit-Wahrscheinlichkeit als hoch ein — diese Schwachstelle wird aktiv in freier Wildbahn ausgenutzt und sollte priorisiert behoben werden.

Welche Sprachen oder Plattformen sind von CWE-259 betroffen?

MITRE lists the following affected platforms: ICS/OT.

Wie kann ich CWE-259 verhindern?

For outbound authentication: store passwords outside of the code in a strongly-protected, encrypted configuration file or database that is protected from access by all outsiders, including other local users on the same system. Properly protect the key (CWE-320). If you cannot use encryption to protect the file, then make sure that the permissions are as restrictive as possible. For inbound authentication: Rather than hard-code a default username and password for first time logins, utilize a…

Wie erkennt und behebt Plexicus CWE-259?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-259 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-259?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/259.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

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