CWE-766 关键变量被公开声明

Critical Data Element Declared Public

结构: Simple

Abstraction: Variant

状态: Incomplete

被利用可能性: unkown

基本描述

The software declares a critical variable, field, or member to be public when intended security policy requires it to be private.

扩展描述

This issue makes it more difficult to maintain the software, which indirectly affects security by making it more difficult or time-consuming to find and/or fix vulnerabilities. It also might make it easier to introduce vulnerabilities.

相关缺陷

  • cwe_Nature: ChildOf cwe_CWE_ID: 1061 cwe_View_ID: 1000 cwe_Ordinal: Primary

适用平台

Language: [{'cwe_Name': 'C++', 'cwe_Prevalence': 'Undetermined'}, {'cwe_Name': 'C#', 'cwe_Prevalence': 'Undetermined'}, {'cwe_Name': 'Java', 'cwe_Prevalence': 'Undetermined'}]

常见的影响

范围 影响 注释
['Integrity', 'Confidentiality'] ['Read Application Data', 'Modify Application Data'] Making a critical variable public allows anyone with access to the object in which the variable is contained to alter or read the value.
Other Reduce Maintainability

可能的缓解方案

Implementation

策略:

Data should be private, static, and final whenever possible. This will assure that your code is protected by instantiating early, preventing access, and preventing tampering.

示例代码

例

The following example declares a critical variable public, making it accessible to anyone with access to the object in which it is contained.

bad C++

public: char* password;

Instead, the critical data should be declared private.

good C++

private: char* password;

Even though this example declares the password to be private, there are other possible issues with this implementation, such as the possibility of recovering the password from process memory (CWE-257).

例

The following example shows a basic user account class that includes member variables for the username and password as well as a public constructor for the class and a public method to authorize access to the user account.

bad C++

#define MAX_PASSWORD_LENGTH 15
#define MAX_USERNAME_LENGTH 15

class UserAccount
{
public:
UserAccount(char username, char password)
{
if ((strlen(username) > MAX_USERNAME_LENGTH) ||
(strlen(password) > MAX_PASSWORD_LENGTH)) {
ExitError("Invalid username or password");
}
strcpy(this->username, username);
strcpy(this->password, password);
}


int authorizeAccess(char username, char password)
{
if ((strlen(username) > MAX_USERNAME_LENGTH) ||
(strlen(password) > MAX_PASSWORD_LENGTH)) {
ExitError("Invalid username or password");
}
// if the username and password in the input parameters are equal to

// the username and password of this account class then authorize access
if (strcmp(this->username, username) ||
strcmp(this->password, password))
return 0;

// otherwise do not authorize access
else
return 1;
}

char username[MAX_USERNAME_LENGTH+1];
char password[MAX_PASSWORD_LENGTH+1];
};

However, the member variables username and password are declared public and therefore will allow access and changes to the member variables to anyone with access to the object. These member variables should be declared private as shown below to prevent unauthorized access and changes.

good C++

class UserAccount
{
public:
...


private:
char username[MAX_USERNAME_LENGTH+1];
char password[MAX_PASSWORD_LENGTH+1];
};

分析过的案例

标识 说明 链接

分类映射

映射的分类名 ImNode ID Fit Mapped Node Name
CLASP Failure to protect stored data from modification
The CERT Oracle Secure Coding Standard for Java (2011) OBJ01-J Declare data members as private and provide accessible wrapper methods
Software Fault Patterns SFP28 Unexpected access points
OMG ASCMM ASCMM-MNT-15

引用