CWE-760 Variant Incomplete

Use of a One-Way Hash with a Predictable Salt

This vulnerability occurs when an application uses a one-way hash (like for password storage) but combines it with a predictable or easily guessed salt. This undermines the security benefit of…

Definition

What is CWE-760?

This vulnerability occurs when an application uses a one-way hash (like for password storage) but combines it with a predictable or easily guessed salt. This undermines the security benefit of salting, making pre-computed attack methods like rainbow tables highly effective.
Using a predictable salt, such as a username or a static string, allows attackers to bypass the primary defense salting provides. Attackers can pre-generate massive lookup tables (rainbow tables) for that specific salt, enabling them to quickly reverse hashes and recover credentials. This effectively nullifies the security advantage that a random, unique salt is meant to deliver. It's important to understand that even a strong, random salt is not a complete solution against determined attackers with significant resources, as hashing algorithms are designed for speed. Modern password cracking using cloud or specialized hardware can still be effective. For robust protection, consider adaptive, computationally expensive hash functions (like Argon2, scrypt, or bcrypt) designed specifically for passwords. Identifying and fixing these predictable salt patterns across a large codebase can be challenging; an ASPM platform like Plexicus can automatically detect such flaws via SAST and use AI to provide specific remediation guidance, streamlining the fix process.
Auswirkungen in der Praxis

Real-world CVEs caused by CWE-760

  • CVE-2008-4905

    Blogging software uses a hard-coded salt when calculating a password hash.

  • CVE-2002-1657

    Database server uses the username for a salt when encrypting passwords, simplifying brute force attacks.

  • CVE-2001-0967

    Server uses a constant salt when encrypting passwords, simplifying brute force attacks.

  • CVE-2005-0408

    chain: product generates predictable MD5 hashes using a constant value combined with username, allowing authentication bypass.

Wie Angreifer es ausnutzen

Angreiferpfad Schritt für Schritt

  1. 1

    Identifiziere einen Codepfad, der nicht vertrauenswürdige Eingaben ohne Validierung verarbeitet.

  2. 2

    Erzeuge eine Payload, die das unsichere Verhalten auslöst — Injection, Traversal, Overflow oder Logik-Missbrauch.

  3. 3

    Liefere die Payload über einen normalen Request aus und beobachte die Reaktion der Anwendung.

  4. 4

    Iteriere, bis die Antwort Daten preisgibt, Angreifer-Code ausführt oder Berechtigungen eskaliert.

Verwundbares Codebeispiel

Vulnerable pseudo

MITRE hat kein Codebeispiel für diese CWE veröffentlicht. Das untenstehende Muster ist illustrativ — kanonische Referenzen findest du unter Ressourcen.

Verwundbar pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
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-760

  • Architecture and Design Use an adaptive hash function that can be configured to change the amount of computational effort needed to compute the hash, such as the number of iterations ("stretching") or the amount of memory required. Some hash functions perform salting automatically. These functions can significantly increase the overhead for a brute force attack compared to intentionally-fast functions such as MD5. For example, rainbow table attacks can become infeasible due to the high computing overhead. Finally, since computing power gets faster and cheaper over time, the technique can be reconfigured to increase the workload without forcing an entire replacement of the algorithm in use. Some hash functions that have one or more of these desired properties include bcrypt [REF-291], scrypt [REF-292], and PBKDF2 [REF-293]. While there is active debate about which of these is the most effective, they are all stronger than using salts with hash functions with very little computing overhead. Note that using these functions can have an impact on performance, so they require special consideration to avoid denial-of-service attacks. However, their configurability provides finer control over how much CPU and memory is used, so it could be adjusted to suit the environment's needs.
  • Implementation If a technique that requires extra computational effort can not be implemented, then for each password that is processed, generate a new random salt using a strong random number generator with unpredictable seeds. Add the salt to the plaintext password before hashing it. When storing the hash, also store the salt. Do not use the same salt for every password.
Erkennungssignale

How to detect CWE-760

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-760 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.

Demo anfordern Plexicus kostenlos testen
Häufig gestellte Fragen

Frequently asked questions

Was ist CWE-760?

This vulnerability occurs when an application uses a one-way hash (like for password storage) but combines it with a predictable or easily guessed salt. This undermines the security benefit of salting, making pre-computed attack methods like rainbow tables highly effective.

Wie gravierend ist CWE-760?

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-760 betroffen?

MITRE hat für diese CWE keine betroffenen Plattformen spezifiziert — sie kann in den meisten Anwendungs-Stacks auftreten.

Wie kann ich CWE-760 verhindern?

Use an adaptive hash function that can be configured to change the amount of computational effort needed to compute the hash, such as the number of iterations ("stretching") or the amount of memory required. Some hash functions perform salting automatically. These functions can significantly increase the overhead for a brute force attack compared to intentionally-fast functions such as MD5. For example, rainbow table attacks can become infeasible due to the high computing overhead. Finally,…

Wie erkennt und behebt Plexicus CWE-760?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-760 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-760?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/760.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-760

CWE-916 Parent

Use of Password Hash With Insufficient Computational Effort

This vulnerability occurs when a system protects passwords by hashing them, but uses a hashing algorithm that is too fast or…

CWE-759 Sibling

Use of a One-Way Hash without a Salt

This vulnerability occurs when a system uses a one-way hash function (like MD5 or SHA-256) to protect sensitive data like passwords, but…

Ressourcen

Further reading

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