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CWE-157: Failure to Sanitize Paired Delimiters

 
Failure to Sanitize Paired Delimiters
Weakness ID: 157 (Weakness Variant)Status: Draft
+ Description

Description Summary

The software does not properly handle the characters that are used to mark the beginning and ending of a group of entities, such as parentheses, brackets, and braces.
+ Time of Introduction
  • Implementation
+ Applicable Platforms

Languages

All

+ Common Consequences
ScopeEffect
Integrity

Technical Impact: Unexpected state

+ Demonstrative Examples

Example 1

Paired delimiters might include:

  • < and > angle brackets

  • ( and ) parentheses

  • { and } braces

  • [ and ] square brackets

  • " " double quotes

  • ' ' single quotes

+ Observed Examples
ReferenceDescription
CVE-2004-0956Crash via missing paired delimiter (open double-quote but no closing double-quote).
CVE-2000-1165Crash via message without closing ">".
CVE-2005-2933Buffer overflow via mailbox name with an opening double quote but missing a closing double quote, causing a larger copy than expected.
+ Potential Mitigations

Developers should anticipate that grouping elements will be injected/removed/manipulated in the input vectors of their software system. Use an appropriate combination of black lists and white lists to ensure only valid, expected and appropriate input is processed by the system.

Phase: Implementation

Strategy: Input Validation

Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a whitelist of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.

When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."

Do not rely exclusively on looking for malicious or malformed inputs (i.e., do not rely on a blacklist). A blacklist is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, blacklists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

Use and specify a strong output encoding (such as ISO 8859-1 or UTF 8).

Phase: Implementation

Strategy: Input Validation

Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass whitelist validation schemes by introducing dangerous inputs after they have been checked.

+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness ClassWeakness Class138Improper Neutralization of Special Elements
Development Concepts (primary)699
Research Concepts (primary)1000
+ Research Gaps

Under-studied.

+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
PLOVERGrouping Element / Paired Delimiter
+ Content History
Submissions
Submission DateSubmitterOrganizationSource
PLOVERExternally Mined
Modifications
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigitalExternal
updated Potential_Mitigations, Time_of_Introduction
2008-09-08CWE Content TeamMITREInternal
updated Relationships, Taxonomy_Mappings
2009-07-27CWE Content TeamMITREInternal
updated Potential_Mitigations
2011-03-29CWE Content TeamMITREInternal
updated Potential_Mitigations
2011-06-01CWE Content TeamMITREInternal
updated Common_Consequences
2011-06-27CWE Content TeamMITREInternal
updated Common_Consequences
Previous Entry Names
Change DatePrevious Entry Name
2008-04-11Grouping Element / Paired Delimiter
Page Last Updated: September 12, 2011