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cwe:cn:definition:311

CWE-311:敏感数据加密缺失

Description Summary

The software does not encrypt sensitive or critical information before storage or transmission.

Extended Description

The lack of proper data encryption passes up the guarantees of confidentiality, integrity, and accountability that properly implemented encryption conveys.

Likelihood of Exploit

High to Very High

Common Consequences

Scope Technical Impace Note
ConfidentialityRead application dataIf the application does not use a secure channel, such as SSL, to exchange sensitive information, it is possible for an attacker with access to the network traffic to sniff packets from the connection and uncover the data. This attack is not technically difficult, but does require physical access to some portion of the network over which the sensitive data travels. This access is usually somewhere near where the user is connected to the network (such as a colleague on the company network) but can be anywhere along the path from the user to the end server.
Confidentiality
Integrity
Modify application dataOmitting the use of encryption in any program which transfers data over a network of any kind should be considered on par with delivering the data sent to each user on the local networks of both the sender and receiver. Worse, this omission allows for the injection of data into a stream of communication between two parties – with no means for the victims to separate valid data from invalid. In this day of widespread network attacks and password collection sniffers, it is an unnecessary risk to omit encryption from the design of any system which might benefit from it.

Detection Methods

Detection Method - 1

Manual Analysis

The characterizaton of sensitive data often requires domain-specific understanding, so manual methods are useful. However, manual efforts might not achieve desired code coverage within limited time constraints. Black box methods may produce artifacts (e.g. stored data or unencrypted network transfer) that require manual evaluation.

Detection Method - 2

Automated Analysis

Automated measurement of the entropy of an input/output source may indicate the use or lack of encryption, but human analysis is still required to distinguish intentionally-unencrypted data (e.g. metadata) from sensitive data.

Detection Method - 3

Manual Static Analysis - Binary / Bytecode

According to SOAR, the following detection techniques may be useful:

Detection Method - 4

=== Dynamic Analysis with automated results interpretation === According to SOAR, the following detection techniques may be useful:

Detection Method - 5

Dynamic Analysis with manual results interpretation

According to SOAR, the following detection techniques may be useful:

Detection Method - 6

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Detection Method - 7

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Detection Method - 8

Architecture / Design Review

According to SOAR, the following detection techniques may be useful:

Potential Mitigations

Mitigation - 1

Requirements

Clearly specify which data or resources are valuable enough that they should be protected by encryption. Require that any transmission or storage of this data/resource should use well-vetted encryption algorithms.

Mitigation - 2

Architecture and Design

Strategy:Threat Modeling

Using threat modeling or other techniques, assume that the data can be compromised through a separate vulnerability or weakness, and determine where encryption will be most effective. Ensure that data that should be private is not being inadvertently exposed using weaknesses such as insecure permissions (CWE-732). [R.311.1]

Mitigation - 3

Architecture and Design

Ensure that encryption is properly integrated into the system design, including but not necessarily limited to:

Identify the separate needs and contexts for encryption:

Mitigation - 4

Architecture and Design

Strategy:Libraries or Frameworks

When there is a need to store or transmit sensitive data, use strong, up-to-date cryptographic algorithms to encrypt that data. Select a well-vetted algorithm that is currently considered to be strong by experts in the field, and use well-tested implementations. As with all cryptographic mechanisms, the source code should be available for analysis.

For example, US government systems require FIPS 140-2 certification.

Do not develop custom or private cryptographic algorithms. They will likely be exposed to attacks that are well-understood by cryptographers. Reverse engineering techniques are mature. If the algorithm can be compromised if attackers find out how it works, then it is especially weak.

Periodically ensure that the cryptography has not become obsolete. Some older algorithms, once thought to require a billion years of computing time, can now be broken in days or hours. This includes MD4, MD5, SHA1, DES, and other algorithms that were once regarded as strong. [R.327.4]

2013/05/30 09:37

Mitigation - 5

Architecture and Design

Strategy:Separation of Privilege

Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.

Ensure that appropriate compartmentalization is built into the system design and that the compartmentalization serves to allow for and further reinforce privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide when it is appropriate to use and to drop system privileges.

2013/05/30 12:46

Mitigation - 6

Implementation Architecture and Design

When using industry-approved techniques, use them correctly. Don't cut corners by skipping resource-intensive steps (CWE-325). These steps are often essential for preventing common attacks.

2013/05/30 09:37

Mitigation - 7

Implementation

Strategy:Identify and Reduce Attack Surface

Use naming conventions and strong types to make it easier to spot when sensitive data is being used. When creating structures, objects, or other complex entities, separate the sensitive and non-sensitive data as much as possible.

2013/05/30 09:37

Demonstrative Examples

Example - 1

This code writes a user's login information to a cookie so the user does not have to login again later.

function persistLogin($username, $password){ 
$data = array("username" => $username, "password"=> $password); 
setcookie ("userdata", $data); 
 
} 

The code stores the user's username and password in plaintext in a cookie on the user's machine. This exposes the user's login information if their computer is compromised by an attacker. Even if the user's machine is not compromised, this weakness combined with cross-site scripting (CWE-79) could allow an attacker to remotely copy the cookie.

Also note this example code also exhibits Plaintext Storage in a Cookie (CWE-315).

2013/05/30 13:23

Example - 2

The following code attempts to establish a connection, read in a password, then store it to a buffer.

server.sin_family = AF_INET; hp = gethostbyname(argv[1]); 
if (hp==NULL) error("Unknown host"); 
memcpy( (char *)&server.sin_addr,(char *)hp->h_addr,hp->h_length); 
if (argc < 3) port = 80; 
else port = (unsigned short)atoi(argv[3]); 
server.sin_port = htons(port); 
if (connect(sock, (struct sockaddr *)&server, sizeof server) < 0) error("Connecting"); 
... 
while ((n=read(sock,buffer,BUFSIZE-1))!=-1) { 
 
write(dfd,password_buffer,n); 
... 
 
 

While successful, the program does not encrypt the data before writing it to a buffer, possibly exposing it to unauthorized actors.

2013/05/30 13:23

Example - 3

The following code attempts to establish a connection to a site to communicate sensitive information.

try { 
URL u = new URL("http://www.secret.example.org/"); 
HttpURLConnection hu = (HttpURLConnection) u.openConnection(); 
hu.setRequestMethod("PUT"); 
hu.connect(); 
OutputStream os = hu.getOutputStream(); 
hu.disconnect(); 
 
} 
catch (IOException e) { 
//... 
 
} 

Though a connection is successfully made, the connection is unencrypted and it is possible that all sensitive data sent to or received from the server will be read by unintended actors.

2013/05/30 13:23

Observed Examples

Reference Description
CVE-2009-2272password and username stored in cleartext in a cookie
CVE-2009-1466password stored in cleartext in a file with insecure permissions
CVE-2009-0152chat program disables SSL in some circumstances even when the user says to use SSL.
CVE-2009-1603Chain: product uses an incorrect public exponent when generating an RSA key, which effectively disables the encryption
CVE-2009-0964storage of unencrypted passwords in a database
CVE-2008-6157storage of unencrypted passwords in a database
CVE-2008-6828product stores a password in cleartext in memory
CVE-2008-1567storage of a secret key in cleartext in a temporary file
CVE-2008-0174SCADA product uses HTTP Basic Authentication, which is not encrypted
CVE-2007-5778login credentials stored unencrypted in a registry key
CVE-2002-1949Passwords transmitted in cleartext.
CVE-2008-4122Chain: Use of HTTPS cookie without “secure” flag causes it to be transmitted across unencrypted HTTP.
CVE-2008-3289Product sends password hash in cleartext in violation of intended policy.
CVE-2008-4390Remote management feature sends sensitive information including passwords in cleartext.
CVE-2007-5626Backup routine sends password in cleartext in email.
CVE-2004-1852Product transmits Blowfish encryption key in cleartext.
CVE-2008-0374Printer sends configuration information, including administrative password, in cleartext.
CVE-2007-4961Chain: cleartext transmission of the MD5 hash of password enables attacks against a server that is susceptible to replay (CWE-294).
CVE-2007-4786Product sends passwords in cleartext to a log server.
CVE-2005-3140Product sends file with cleartext passwords in e-mail message intended for diagnostic purposes.
cwe/cn/definition/311.txt · 最后更改: 2014/09/04 14:31 (外部编辑)