This makes it easier for attackers to pre-compute the hash value using dictionary attack techniques such as rainbow tables, effectively disabling the protection that an unpredictable salt would provide.
It should be noted that, despite common perceptions, the use of a good salt with a hash does not sufficiently increase the effort for an attacker who is targeting an individual password, or who has a large amount of computing resources available, such as with cloud-based services or specialized, inexpensive hardware. Offline password cracking can still be effective if the hash function is not expensive to compute; many cryptographic functions are designed to be efficient and can be vulnerable to attacks using massive computing resources, even if the hash is cryptographically strong. The use of a salt only slightly increases the computing requirements for an attacker compared to other strategies such as adaptive hash functions. See CWE-916 for more details.
| Impact | Details |
|---|---|
|
Bypass Protection Mechanism |
Scope: Access Control |
| Phase(s) | Mitigation |
|---|---|
|
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. Effectiveness: High |
|
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.
Effectiveness: Limited Note:
Be aware that salts will not reduce the workload of a targeted attack against an individual hash (such as the password for a critical person), and in general they are less effective than other hashing techniques such as increasing the computation time or memory overhead. Without a built-in workload, modern attacks can compute large numbers of hashes, or even exhaust the entire space of all possible passwords, within a very short amount of time, using massively-parallel computing and GPU, ASIC, or FPGA hardware.
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| Nature | Type | ID | Name |
|---|---|---|---|
| ChildOf | Base Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. | 916 | Use of Password Hash With Insufficient Computational Effort |
| Nature | Type | ID | Name |
|---|---|---|---|
| MemberOf | Category Category - a CWE entry that contains a set of other entries that share a common characteristic. | 1013 | Encrypt Data |
| Phase | Note |
|---|---|
| Implementation | REALIZATION: This weakness is caused during implementation of an architectural security tactic. |
Note: this is a curated list of examples for users to understand the variety of ways in which this weakness can be introduced. It is not a complete list of all CVEs that are related to this CWE entry.
| Reference | Description |
|---|---|
|
Blogging software uses a hard-coded salt when calculating a password hash.
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Database server uses the username for a salt when encrypting passwords, simplifying brute force attacks.
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Server uses a constant salt when encrypting passwords, simplifying brute force attacks.
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chain: product generates predictable MD5 hashes using a constant value combined with username, allowing authentication bypass.
|
| Method | Details |
|---|---|
|
Automated Static Analysis |
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.)
Effectiveness: High |
| Nature | Type | ID | Name |
|---|---|---|---|
| MemberOf | CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. | 958 | SFP Secondary Cluster: Broken Cryptography |
| MemberOf | CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. | 1346 | OWASP Top Ten 2021 Category A02:2021 - Cryptographic Failures |
| MemberOf | CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. | 1402 | Comprehensive Categorization: Encryption |
Rationale
This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.Comments
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.Maintenance
| Submissions | ||
|---|---|---|
| Submission Date | Submitter | Organization |
|
2009年03月03日
(CWE 1.3, 2009年03月10日) |
CWE Content Team | MITRE |
| Modifications | ||
| Modification Date | Modifier | Organization |
|
2025年09月09日
(CWE 4.18, 2025年09月09日) |
CWE Content Team | MITRE |
| updated References | ||
| 2023年06月29日 | CWE Content Team | MITRE |
| updated Mapping_Notes | ||
| 2023年04月27日 | CWE Content Team | MITRE |
| updated Detection_Factors, References, Relationships | ||
| 2023年01月31日 | CWE Content Team | MITRE |
| updated Description | ||
| 2021年10月28日 | CWE Content Team | MITRE |
| updated Relationships | ||
| 2021年07月20日 | CWE Content Team | MITRE |
| updated Maintenance_Notes | ||
| 2020年02月24日 | CWE Content Team | MITRE |
| updated Relationships | ||
| 2019年06月20日 | CWE Content Team | MITRE |
| updated Type | ||
| 2018年03月27日 | CWE Content Team | MITRE |
| updated References | ||
| 2017年11月08日 | CWE Content Team | MITRE |
| updated Modes_of_Introduction, References, Relationships | ||
| 2017年01月19日 | CWE Content Team | MITRE |
| updated Relationships | ||
| 2014年07月30日 | CWE Content Team | MITRE |
| updated Relationships | ||
| 2014年02月18日 | CWE Content Team | MITRE |
| updated Potential_Mitigations, References | ||
| 2013年02月21日 | CWE Content Team | MITRE |
| updated Description, Potential_Mitigations, References, Relationships, Type | ||
| 2012年10月30日 | CWE Content Team | MITRE |
| updated Potential_Mitigations, References | ||
| 2012年05月11日 | CWE Content Team | MITRE |
| updated References, Relationships | ||
| 2011年06月01日 | CWE Content Team | MITRE |
| updated Common_Consequences | ||
| 2011年03月29日 | CWE Content Team | MITRE |
| updated Observed_Examples | ||
| 2010年02月16日 | CWE Content Team | MITRE |
| updated References | ||
| 2009年10月29日 | CWE Content Team | MITRE |
| updated Observed_Examples, Relationships | ||
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