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Missing Encryption of Sensitive Data

Draft Class
Structure: Simple
Description

This vulnerability occurs when an application stores or sends sensitive information without first encrypting it, leaving the data exposed.

This vulnerability occurs when an application stores or sends sensitive information without first encrypting it, leaving the data exposed.
Extended Description

Sensitive data like passwords, financial details, personal identification numbers, or authentication tokens must be encrypted both at rest (in databases, logs, or files) and in transit (over networks). When developers skip this step, any attacker who gains access to the storage or can intercept the network traffic can read the information directly, leading to immediate data breaches, identity theft, or system compromise. Preventing this requires a proactive security mindset. Always use strong, standard encryption algorithms (like AES for storage and TLS for transmission) and manage encryption keys securely. Treat any data that could harm users or your organization if exposed as 'sensitive' and encrypt it by default, rather than trying to decide case-by-case. Regularly audit your code and configurations to ensure no critical data flows or persists in plaintext.
Common Consequences 2
Scope: Confidentiality

Impact: Read Application Data

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.

Scope: ConfidentialityIntegrity

Impact: Modify Application Data

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.
Detection Methods 8
Manual AnalysisHigh
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.
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.
Manual Static Analysis - Binary or BytecodeSOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies
Dynamic Analysis with Automated Results InterpretationSOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Web Application Scanner Web Services Scanner Database Scanners
Dynamic Analysis with Manual Results InterpretationHigh
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Network Sniffer ``` Cost effective for partial coverage: ``` Fuzz Tester Framework-based Fuzzer Automated Monitored Execution Man-in-the-middle attack tool
Manual Static Analysis - Source CodeHigh
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Focused Manual Spotcheck - Focused manual analysis of source Manual Source Code Review (not inspections)
Automated Static Analysis - Source CodeSOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Context-configured Source Code Weakness Analyzer
Architecture or Design ReviewHigh
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.) Formal Methods / Correct-By-Construction ``` Cost effective for partial coverage: ``` Attack Modeling
Potential Mitigations 6
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
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 product) 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. Using threat modeling or other techniques, assume that 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 (Incorrect Permission Assignment for Critical Resource). [REF-7]
Phase: 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. [REF-267]
Phase: 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 the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Phase: ImplementationArchitecture and Design
When using industry-approved techniques, use them correctly. Don't cut corners by skipping resource-intensive steps (Missing Cryptographic Step). These steps are often essential for preventing common attacks.
Phase: Implementation

Strategy: Attack Surface Reduction

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.

Effectiveness: Defense in Depth
Demonstrative Examples 3

ID : DX-40

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

Code Example:

Bad
PHP
php
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 (Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) could allow an attacker to remotely copy the cookie.
Also note this example code also exhibits Plaintext Storage in a Cookie (Cleartext Storage of Sensitive Information in a Cookie).

ID : DX-41

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

Code Example:

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

ID : DX-42

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

Code Example:

Bad
Java
java

//...* }

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 20
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 (Authentication Bypass by Capture-replay).
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.
References 7
The CLASP Application Security Process
Secure Software, Inc.
2005
https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf(2024-11-17)
ID: REF-18
Writing Secure Code
Michael Howard and David LeBlanc
Microsoft Press
04-12-2002
https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223
ID: REF-7
24 Deadly Sins of Software Security
Michael Howard, David LeBlanc, and John Viega
McGraw-Hill
2010
ID: REF-44
Top 25 Series - Rank 10 - Missing Encryption of Sensitive Data
Frank Kim
SANS Software Security Institute
26-02-2010
https://www.sans.org/blog/top-25-series-rank-10-missing-encryption-of-sensitive-data/(2025-07-29)
ID: REF-265
The Art of Software Security Assessment
Mark Dowd, John McDonald, and Justin Schuh
Addison Wesley
2006
ID: REF-62
FIPS PUB 140-2: SECURITY REQUIREMENTS FOR CRYPTOGRAPHIC MODULES
Information Technology Laboratory, National Institute of Standards and Technology
25-05-2001
https://csrc.nist.gov/files/pubs/fips/140-2/upd2/final/docs/fips1402.pdf(2025-05-21)
ID: REF-267
State-of-the-Art Resources (SOAR) for Software Vulnerability Detection, Test, and Evaluation
Gregory Larsen, E. Kenneth Hong Fong, David A. Wheeler, and Rama S. Moorthy
07-2014
https://www.ida.org/-/media/feature/publications/s/st/stateoftheart-resources-soar-for-software-vulnerability-detection-test-and-evaluation/p-5061.ashx(2025-09-05)
ID: REF-1479
Likelihood of Exploit

High

Applicable Platforms
Languages:
Not Language-Specific : Undetermined
Modes of Introduction
Architecture and Design
Operation
Related Attack Patterns
Related Weaknesses
ChildOf: Protection Mechanism Failure (CWE-693)
Taxonomy Mapping
  • CLASP
  • OWASP Top Ten 2007
  • OWASP Top Ten 2007
  • OWASP Top Ten 2004
  • WASC
  • The CERT Oracle Secure Coding Standard for Java (2011)
  • Software Fault Patterns
  • ISA/IEC 62443
  • ISA/IEC 62443
  • ISA/IEC 62443
  • ISA/IEC 62443
  • ISA/IEC 62443
Notes
RelationshipThere is an overlapping relationship between insecure storage of sensitive information (Insecure Storage of Sensitive Information) and missing encryption of sensitive information (Missing Encryption of Sensitive Data). Encryption is often used to prevent an attacker from reading the sensitive data. However, encryption does not prevent the attacker from erasing or overwriting the data.