界: Security Features

软件安全不是安全软件。此处我们关注的主题包括身份验证、Access Control、机密性、加密和权限管理。

Key Management: Empty HMAC Key

Abstract

空的 HMAC 密钥可能会削弱系统安全性，一旦出现安全问题将无法轻易修正。

Explanation

使用空的 HMAC 密钥绝非好方法。HMAC 的加密强度依赖于密钥的大小，后者用于计算和验证消息的身份验证值。使用空的密钥会削弱 HMAC 函数的加密强度。
示例 1：下列代码使用空密钥来计算 HMAC：


...
DATA: lo_hmac TYPE Ref To cl_abap_hmac,
             Input_string type string.

CALL METHOD cl_abap_hmac=>get_instance
  EXPORTING
    if_algorithm = 'SHA3'
    if_key       = space
  RECEIVING
    ro_object    = lo_hmac.

" update HMAC with input
lo_hmac->update( if_data = input_string ).

" finalise hmac
lo_digest->final( ).

...

Example 1 中显示的代码可能会成功运行，但有权访问该代码的任何人都能知道它使用的是空 HMAC 密钥。一旦程序发布，除非修补该程序，否则可能无法更改此空 HMAC 密钥。心怀不轨的雇员可以利用手中掌握的信息访问权限破坏 HMAC 函数。另外，Example 1 中的代码还容易受到伪造和密钥恢复攻击的侵害。

References

[1] RFC 2104 - HMAC: Keyed-Hashing for Message Authentication Internet Engineering Task Force (IETF)

[2] New Results on NMAC/HMAC when Instantiated with Popular Hash Functions Journal of Universal Computer Science (J.UCS)

[3] Standards Mapping - Common Weakness Enumeration CWE ID 321

[4] Standards Mapping - Common Weakness Enumeration Top 25 2019 [13] CWE ID 287, [19] CWE ID 798

[5] Standards Mapping - Common Weakness Enumeration Top 25 2020 [14] CWE ID 287, [20] CWE ID 798

[6] Standards Mapping - Common Weakness Enumeration Top 25 2021 [14] CWE ID 287, [16] CWE ID 798

[7] Standards Mapping - Common Weakness Enumeration Top 25 2022 [14] CWE ID 287, [15] CWE ID 798

[8] Standards Mapping - Common Weakness Enumeration Top 25 2023 [13] CWE ID 287, [18] CWE ID 798

[9] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-002450

[10] Standards Mapping - FIPS200 IA

[11] Standards Mapping - General Data Protection Regulation (GDPR) Insufficient Data Protection

[12] Standards Mapping - NIST Special Publication 800-53 Revision 4 SC-12 Cryptographic Key Establishment and Management (P1), SC-13 Cryptographic Protection (P1)

[13] Standards Mapping - NIST Special Publication 800-53 Revision 5 SC-12 Cryptographic Key Establishment and Management, SC-13 Cryptographic Protection

[14] Standards Mapping - OWASP Application Security Verification Standard 4.0 2.6.3 Look-up Secret Verifier Requirements (L2 L3), 2.7.1 Out of Band Verifier Requirements (L1 L2 L3), 2.7.2 Out of Band Verifier Requirements (L1 L2 L3), 2.7.3 Out of Band Verifier Requirements (L1 L2 L3), 2.8.4 Single or Multi Factor One Time Verifier Requirements (L2 L3), 2.8.5 Single or Multi Factor One Time Verifier Requirements (L2 L3), 2.9.1 Cryptographic Software and Devices Verifier Requirements (L2 L3), 2.10.2 Service Authentication Requirements (L2 L3), 2.10.4 Service Authentication Requirements (L2 L3), 3.5.2 Token-based Session Management (L2 L3), 3.7.1 Defenses Against Session Management Exploits (L1 L2 L3), 6.2.1 Algorithms (L1 L2 L3), 6.4.1 Secret Management (L2 L3), 6.4.2 Secret Management (L2 L3), 9.2.3 Server Communications Security Requirements (L2 L3), 10.2.3 Malicious Code Search (L3)

[15] Standards Mapping - OWASP Mobile 2014 M6 Broken Cryptography

[16] Standards Mapping - OWASP Mobile 2024 M10 Insufficient Cryptography

[17] Standards Mapping - OWASP Mobile Application Security Verification Standard 2.0 MASVS-CRYPTO-2

[18] Standards Mapping - OWASP Top 10 2004 A8 Insecure Storage

[19] Standards Mapping - OWASP Top 10 2007 A8 Insecure Cryptographic Storage

[20] Standards Mapping - OWASP Top 10 2010 A7 Insecure Cryptographic Storage

[21] Standards Mapping - OWASP Top 10 2013 A6 Sensitive Data Exposure

[22] Standards Mapping - OWASP Top 10 2017 A3 Sensitive Data Exposure

[23] Standards Mapping - OWASP Top 10 2021 A02 Cryptographic Failures

[24] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.8, Requirement 8.4

[25] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.3.1.3, Requirement 6.5.8, Requirement 8.4

[26] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 6.3.1, Requirement 6.5.3, Requirement 8.4

[27] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.3.1, Requirement 6.5.3, Requirement 8.2.1

[28] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.3.1, Requirement 6.5.3, Requirement 8.2.1

[29] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.3.1, Requirement 6.5.3, Requirement 8.2.1

[30] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.3.1, Requirement 6.5.3, Requirement 8.2.1

[31] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 6.2.4, Requirement 6.5.3, Requirement 6.5.6, Requirement 8.3.2

[32] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 7.2 - Use of Cryptography

[33] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 7.2 - Use of Cryptography, Control Objective B.2.3 - Terminal Software Design

[34] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 7.2 - Use of Cryptography, Control Objective B.2.3 - Terminal Software Design

[35] Standards Mapping - SANS Top 25 2009 Porous Defenses - CWE ID 259

[36] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3210.1 CAT II, APP3350 CAT I

[37] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3210.1 CAT II, APP3350 CAT I

[38] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3210.1 CAT II, APP3350 CAT I

[39] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3210.1 CAT II, APP3350 CAT I

[40] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3210.1 CAT II, APP3350 CAT I

[41] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3210.1 CAT II, APP3350 CAT I

[42] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3210.1 CAT II, APP3350 CAT I

[43] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002010 CAT II

[44] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002010 CAT II

[45] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002010 CAT II

[46] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002010 CAT II

[47] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002010 CAT II

[48] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002010 CAT II

[49] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002010 CAT II

[50] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002010 CAT II

[51] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002010 CAT II

[52] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002010 CAT II

[53] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002010 CAT II

[54] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002010 CAT II

[55] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002010 CAT II

[56] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002010 CAT II

[57] Standards Mapping - Web Application Security Consortium Version 2.00 Information Leakage (WASC-13)

desc.structural.abap.key_management_empty_hmac_key

Abstract

空的 HMAC 密钥可能会削弱系统安全性，一旦出现安全问题将无法轻易修正。

Explanation

使用空 HMAC 密钥绝非好方法。 HMAC 的加密强度取决于密钥的大小，后者用于计算和验证消息的身份验证值。使用空密钥会削弱 HMAC 函数的加密强度。
示例 1：下列代码使用空密钥来计算 HMAC：


...
using (HMAC hmac = HMAC.Create("HMACSHA512"))
{
  string hmacKey = "";
  byte[] keyBytes = Encoding.ASCII.GetBytes(hmacKey);
  hmac.Key = keyBytes;
  ...
}
...

Example 1 中的代码可能会成功运行，但有权访问该代码的任何人都能知道它使用的是空 HMAC 密钥。一旦程序发布，除非修补该程序，否则可能无法更改此空 HMAC 密钥。心怀不轨的雇员可以利用手中掌握的信息访问权限破坏 HMAC 函数。另外，Example 1 中的代码还容易受到伪造和密钥恢复攻击的侵害。