Missing Encryption of Sensitive Data
Weakness ID: 311 (Weakness Base)Status: Draft
+ Description

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.

+ Time of Introduction
  • Architecture and Design
  • Operation
+ Applicable Platforms

Languages

Language-independent

+ Common Consequences
ScopeEffect
Confidentiality

If 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

Omitting 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.

+ Likelihood of Exploit

High to Very High

+ Detection Methods

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.

Effectiveness: High

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.

+ Demonstrative Examples

Example 1

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

(Bad Code)
Example Language:
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 fails to encrypt the data before writing it to a buffer, possibly exposing it to unauthorized actors.

Example 2

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

(Bad Code)
Example Language: Java 
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.

+ Observed Examples
ReferenceDescription
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: failure to set "secure" flag in HTTPS cookie 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.
+ Potential Mitigations

Phase: 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.

Phase: Architecture and Design

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

Phase: Architecture and Design

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

  • Encryption that is needed to store or transmit private data of the users of the system

  • Encryption that is needed to protect the system itself from unauthorized disclosure or tampering

Identify the separate needs and contexts for encryption:

  • One-way (i.e., only the user or recipient needs to have the key). This can be achieved using public key cryptography, or other techniques in which the encrypting party (i.e., the software) does not need to have access to a private key.

  • Two-way (i.e., the encryption can be automatically performed on behalf of a user, but the key must be available so that the plaintext can be automatically recoverable by that user). This requires storage of the private key in a format that is recoverable only by the user (or perhaps by the operating system) in a way that cannot be recovered by others.

Phase: Architecture and Design

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

Phase: Architecture and Design

Select a well-vetted algorithm that is currently considered to be strong by experts in the field, and select well-tested implementations.

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

As with all cryptographic mechanisms, the source code should be available for analysis.

Periodically ensure that you aren't using obsolete cryptography. 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 which were once regarded as strong.

Phase: Architecture and Design

Compartmentalize your 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.

Phases: Implementation; Architecture and Design

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

Phase: Implementation

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.

This makes it easier to spot places in the code where data is being used that is unencrypted.

+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfCategoryCategory310Cryptographic Issues
Development Concepts (primary)699
ChildOfWeakness ClassWeakness Class693Protection Mechanism Failure
Research Concepts (primary)1000
ChildOfCategoryCategory719OWASP Top Ten 2007 Category A8 - Insecure Cryptographic Storage
Weaknesses in OWASP Top Ten (2007) (primary)629
ChildOfCategoryCategory720OWASP Top Ten 2007 Category A9 - Insecure Communications
Weaknesses in OWASP Top Ten (2007)629
ChildOfCategoryCategory729OWASP Top Ten 2004 Category A8 - Insecure Storage
Weaknesses in OWASP Top Ten (2004) (primary)711
ChildOfCategoryCategory8032010 Top 25 - Porous Defenses
Weaknesses in the 2010 CWE/SANS Top 25 Most Dangerous Programming Errors (primary)800
ParentOfWeakness BaseWeakness Base312Cleartext Storage of Sensitive Information
Development Concepts (primary)699
Research Concepts (primary)1000
ParentOfWeakness BaseWeakness Base319Cleartext Transmission of Sensitive Information
Development Concepts (primary)699
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant614Sensitive Cookie in HTTPS Session Without 'Secure' Attribute
Development Concepts (primary)699
Research Concepts (primary)1000
PeerOfWeakness BaseWeakness Base327Use of a Broken or Risky Cryptographic Algorithm
Research Concepts1000
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
CLASPFailure to encrypt data
OWASP Top Ten 2007A8CWE More SpecificInsecure Cryptographic Storage
OWASP Top Ten 2007A9CWE More SpecificInsecure Communications
OWASP Top Ten 2004A8CWE More SpecificInsecure Storage
WASC4Insufficient Transport Layer Protection
+ Related Attack Patterns
CAPEC-IDAttack Pattern Name
(CAPEC Version: 1.4)
65Passively Sniff and Capture Application Code Bound for Authorized Client
117Data Interception Attacks
157Sniffing Attacks
+ References
[REF-11] M. Howard and D. LeBlanc. "Writing Secure Code". Chapter 9, "Protecting Secret Data" Page 299. 2nd Edition. Microsoft. 2002.
[REF-17] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 17: Failure to Protect Stored Data." Page 253. McGraw-Hill. 2010.
+ Content History
Submissions
Submission DateSubmitterOrganizationSource
CLASPExternally Mined
Modifications
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigitalExternal
updated Time of Introduction
2008-08-15VeracodeExternal
Suggested OWASP Top Ten 2004 mapping
2008-09-08CWE Content TeamMITREInternal
updated Common Consequences, Relationships, Other Notes, Taxonomy Mappings
2009-10-29CWE Content TeamMITREInternal
updated Common Consequences, Other Notes
Previous Entry Names
Change DatePrevious Entry Name
2008-04-11Failure to Encrypt Data