Sensitive Data Storage in Improperly Locked Memory
Weakness ID: 591 (Weakness Variant)Status: Draft
+ Description

Description Summary

The application stores sensitive data in memory that is not locked, or that has been incorrectly locked, which might cause the memory to be written to swap files on disk by the virtual memory manager. This can make the data more accessible to external actors.

Extended Description

On Windows systems the VirtualLock function can lock a page of memory to ensure that it will remain present in memory and not be swapped to disk. However, on older versions of Windows, such as 95, 98, or Me, the VirtualLock() function is only a stub and provides no protection. On POSIX systems the mlock() call ensures that a page will stay resident in memory but does not guarantee that the page will not appear in the swap. Therefore, it is unsuitable for use as a protection mechanism for sensitive data. Some platforms, in particular Linux, do make the guarantee that the page will not be swapped, but this is non-standard and is not portable. Calls to mlock() also require supervisor privilege. Return values for both of these calls must be checked to ensure that the lock operation was actually successful.

+ Time of Introduction
  • Implementation
+ Common Consequences

Sensitive data that is written to a swap file may be exposed.

+ Potential Mitigations

Phase: Architecture and Design

Identify data that needs to be protected from swapping and choose platform-appropriate protection mechanisms.

Phase: Implementation

Check return values to ensure locking operations are successful.

+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness BaseWeakness Base413Insufficient Resource Locking
Development Concepts (primary)699
Research Concepts (primary)1000
ChildOfCategoryCategory633Weaknesses that Affect Memory
Resource-specific Weaknesses (primary)631
ChildOfCategoryCategory729OWASP Top Ten 2004 Category A8 - Insecure Storage
Weaknesses in OWASP Top Ten (2004) (primary)711
ChildOfCategoryCategory742CERT C Secure Coding Section 08 - Memory Management (MEM)
Weaknesses Addressed by the CERT C Secure Coding Standard (primary)734
+ Affected Resources
  • Memory
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
OWASP Top Ten 2004A8CWE More SpecificInsecure Storage
CERT C Secure CodingMEM06-CEnsure that sensitive data is not written out to disk
+ Content History
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigitalExternal
updated Time of Introduction
2008-09-08CWE Content TeamMITREInternal
updated Common Consequences, Relationships, Other Notes, Taxonomy Mappings
2008-11-24CWE Content TeamMITREInternal
updated Relationships, Taxonomy Mappings
2009-05-27CWE Content TeamMITREInternal
updated Description, Other Notes
Previous Entry Names
Change DatePrevious Entry Name
2008-04-11Memory Locking