CWE-329
Generation of Predictable IV with CBC Mode
2006-07-19
00h00 +00:00
00h00 +00:00
指定 CWE 通知
掌握特定 CWE 的任何變更。
名稱: Generation of Predictable IV with CBC Mode
The product generates and uses a predictable initialization Vector (IV) with Cipher Block Chaining (CBC) Mode, which causes algorithms to be susceptible to dictionary attacks when they are encrypted under the same key.
一般資訊
背景詳情
引入方式
Implementation : Developers might dismiss the importance of an unpredictable IV and choose an easier implementation to save effort, weakening the scheme in the process.適用平台
程式語言
類別： Not Language-Specific (Undetermined)技術
類別： ICS/OT (Undetermined)常見後果
| 範圍 | 影響 | 可能性 |
|---|---|---|
| Confidentiality | Read Application Data 注意：If the IV is not properly initialized, data that is encrypted can be compromised and leak information. |
觀察到的案例
| 參考資料 | 描述 |
|---|---|
CVE-2020-5408 | encryption functionality in an authentication framework uses a fixed null IV with CBC mode, allowing attackers to decrypt traffic in applications that use this functionality |
CVE-2017-17704 | messages for a door-unlocking product use a fixed IV in CBC mode, which is the same after each restart |
CVE-2017-11133 | application uses AES in CBC mode, but the pseudo-random secret and IV are generated using math.random, which is not cryptographically strong. |
CVE-2007-3528 | Blowfish-CBC implementation constructs an IV where each byte is calculated modulo 8 instead of modulo 256, resulting in less than 12 bits for the effective IV length, and less than 4096 possible IV values. |
CVE-2011-3389 | BEAST attack in SSL 3.0 / TLS 1.0. In CBC mode, chained initialization vectors are non-random, allowing decryption of HTTPS traffic using a chosen plaintext attack. |
潛在緩解措施
Phases : ImplementationNIST recommends two methods of generating unpredictable IVs for CBC mode [REF-1172]. The first is to generate the IV randomly. The second method is to encrypt a nonce with the same key and cipher to be used to encrypt the plaintext. In this case the nonce must be unique but can be predictable, since the block cipher will act as a pseudo random permutation.
偵測方法
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.)有效性 : High
漏洞對應備注
理由說明 : 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.備註 : 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.
備注
As of CWE 4.5, terminology related to randomness, entropy, and predictability can vary widely. Within the developer and other communities, "randomness" is used heavily. However, within cryptography, "entropy" is distinct, typically implied as a measurement. There are no commonly-used definitions, even within standards documents and cryptography papers. Future versions of CWE will attempt to define these terms and, if necessary, distinguish between them in ways that are appropriate for different communities but do not reduce the usability of CWE for mapping, understanding, or other scenarios.參考資料
REF-62
The Art of Software Security AssessmentMark Dowd, John McDonald, Justin Schuh.
REF-18
The CLASP Application Security ProcessSecure Software, Inc..
https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf
REF-1171
Why IND-CPA implies randomized encryptionMatthew Green.
https://blog.cryptographyengineering.com/why-ind-cpa-implies-randomized-encryption/
REF-1172
Recommendation for Block Cipher Modes of OperationNIST.
https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38a.pdf
提交
| 名稱 | 機構 | 日期 | 發布日期 | Version |
|---|---|---|---|---|
| CLASP | Draft 3 |
修改記錄
| 名稱 | 機構 | 日期 | 備註 |
|---|---|---|---|
| Eric Dalci | Cigital | updated Time_of_Introduction | |
| CWE Content Team | MITRE | updated Background_Details, Common_Consequences, Functional_Areas, Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Common_Consequences | |
| CWE Content Team | MITRE | updated References, Relationships | |
| CWE Content Team | MITRE | updated Demonstrative_Examples, Potential_Mitigations | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Applicable_Platforms, Demonstrative_Examples | |
| CWE Content Team | MITRE | updated Demonstrative_Examples | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Background_Details, Common_Consequences, Demonstrative_Examples, Description, Modes_of_Introduction, Name, Observed_Examples, Potential_Mitigations, References, Relationships | |
| CWE Content Team | MITRE | updated Description, Maintenance_Notes, Name, References | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Applicable_Platforms | |
| CWE Content Team | MITRE | updated Detection_Factors, Modes_of_Introduction, Relationships, Time_of_Introduction | |
| CWE Content Team | MITRE | updated Mapping_Notes | |
| CWE Content Team | MITRE | updated Relationships, Weakness_Ordinalities |
