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Common Weakness Enumeration

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CWE-130: Improper Handling of Length Parameter Inconsistency

 
Improper Handling of Length Parameter Inconsistency
Weakness ID: 130 (Weakness Variant)Status: Incomplete
+ Description

Description Summary

The software parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.

Extended Description

If an attacker can manipulate the length parameter associated with an input such that it is inconsistent with the actual length of the input, this can be leveraged to cause the target application to behave in unexpected, and possibly, malicious ways. One of the possible motives for doing so is to pass in arbitrarily large input to the application. Another possible motivation is the modification of application state by including invalid data for subsequent properties of the application. Such weaknesses commonly lead to attacks such as buffer overflows and execution of arbitrary code.

+ Alternate Terms
length manipulation
length tampering
+ Time of Introduction
  • Architecture and Design
  • Implementation
+ Applicable Platforms

Languages

C: (Sometimes)

C++: (Sometimes)

All

+ Common Consequences
ScopeEffect
Other

Technical Impact: Varies by context

+ Demonstrative Examples

Example 1

In the following C/C++ example the method processMessageFromSocket() will get a message from a socket, placed into a buffer, and will parse the contents of the buffer into a structure that contains the message length and the message body. A for loop is used to copy the message body into a local character string which will be passed to another method for processing.

(Bad Code)
Example Languages: C and C++ 
int processMessageFromSocket(int socket) {
int success;

char buffer[BUFFER_SIZE];
char message[MESSAGE_SIZE];

// get message from socket and store into buffer
//Ignoring possibliity that buffer > BUFFER_SIZE
if (getMessage(socket, buffer, BUFFER_SIZE) > 0) {

// place contents of the buffer into message structure
ExMessage *msg = recastBuffer(buffer);

// copy message body into string for processing
int index;
for (index = 0; index < msg->msgLength; index++) {
message[index] = msg->msgBody[index];
}
message[index] = '\0';

// process message
success = processMessage(message);
}
return success;
}

However, the message length variable from the structure is used as the condition for ending the for loop without validating that the message length variable accurately reflects the length of message body. This can result in a buffer over read by reading from memory beyond the bounds of the buffer if the message length variable indicates a length that is longer than the size of a message body (CWE-130).

+ Observed Examples
ReferenceDescription
CVE-2009-2299Web application firewall consumes excessive memory when an HTTP request contains a large Content-Length value but no POST data.
CVE-2001-0825Buffer overflow in internal string handling routine allows remote attackers to execute arbitrary commands via a length argument of zero or less, which disables the length check.
CVE-2001-1186Web server allows remote attackers to cause a denial of service via an HTTP request with a content-length value that is larger than the size of the request, which prevents server from timing out the connection.
CVE-2001-0191Service does not properly check the specified length of a cookie, which allows remote attackers to execute arbitrary commands via a buffer overflow, or brute force authentication by using a short cookie length.
CVE-2003-0429Traffic analyzer allows remote attackers to cause a denial of service and possibly execute arbitrary code via invalid IPv4 or IPv6 prefix lengths, possibly triggering a buffer overflow.
CVE-2000-0655Chat client allows remote attackers to cause a denial of service or execute arbitrary commands via a JPEG image containing a comment with an illegal field length of 1.
CVE-2004-0492Server allows remote attackers to cause a denial of service and possibly execute arbitrary code via a negative Content-Length HTTP header field causing a heap-based buffer overflow.
CVE-2004-0201 Help program allows remote attackers to execute arbitrary commands via a heap-based buffer overflow caused by a .CHM file with a large length field
CVE-2003-0825Name services does not properly validate the length of certain packets, which allows attackers to cause a denial of service and possibly execute arbitrary code. Can overlap zero-length issues
CVE-2004-0095Policy manager allows remote attackers to cause a denial of service (memory consumption and crash) and possibly execute arbitrary code via an HTTP POST request with an invalid Content-Length value.
CVE-2004-0826Heap-based buffer overflow in library allows remote attackers to execute arbitrary code via a modified record length field in an SSLv2 client hello message.
CVE-2004-0808When domain logons are enabled, server allows remote attackers to cause a denial of service via a SAM_UAS_CHANGE request with a length value that is larger than the number of structures that are provided.
CVE-2002-1357Multiple SSH2 servers and clients do not properly handle packets or data elements with incorrect length specifiers, which may allow remote attackers to cause a denial of service or possibly execute arbitrary code.
CVE-2004-0774Server allows remote attackers to cause a denial of service (CPU and memory exhaustion) via a POST request with a Content-Length header set to -1.
CVE-2004-0989Multiple buffer overflows in xml library that may allow remote attackers to execute arbitrary code via long URLs.
CVE-2004-0568Application does not properly validate the length of a value that is saved in a session file, which allows remote attackers to execute arbitrary code via a malicious session file (.ht), web site, or Telnet URL contained in an e-mail message, triggering a buffer overflow.
CVE-2003-0327Server allows remote attackers to cause a denial of service via a remote password array with an invalid length, which triggers a heap-based buffer overflow.
CVE-2003-0345Product allows remote attackers to cause a denial of service and possibly execute arbitrary code via an SMB packet that specifies a smaller buffer length than is required.
CVE-2004-0430Server allows remote attackers to execute arbitrary code via a LoginExt packet for a Cleartext Password User Authentication Method (UAM) request with a PathName argument that includes an AFPName type string that is longer than the associated length field.
CVE-2005-0064PDF viewer allows remote attackers to execute arbitrary code via a PDF file with a large /Encrypt /Length keyLength value.
CVE-2004-0413SVN client trusts the length field of SVN protocol URL strings, which allows remote attackers to cause a denial of service and possibly execute arbitrary code via an integer overflow that leads to a heap-based buffer overflow.
CVE-2004-0940Is effectively an accidental double increment of a counter that prevents a length check conditional from exiting a loop.
CVE-2002-1235Length field of a request not verified.
CVE-2005-3184Buffer overflow by modifying a length value.
SECUNIA:18747Length field inconsistency crashes cell phone.
+ Potential Mitigations

Phase: Implementation

When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data.

Phase: Implementation

Do not let the user control the size of the buffer.

Phase: Implementation

Validate that the length of the user-supplied data is consistent with the buffer size.

+ Weakness Ordinalities
OrdinalityDescription
Primary
(where the weakness exists independent of other weaknesses)
+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness ClassWeakness Class119Improper Restriction of Operations within the Bounds of a Memory Buffer
Development Concepts (primary)699
ChildOfWeakness VariantWeakness Variant240Improper Handling of Inconsistent Structural Elements
Research Concepts (primary)1000
ChildOfCategoryCategory896SFP Cluster: Tainted Input
Software Fault Pattern (SFP) Clusters (primary)888
CanPrecedeWeakness BaseWeakness Base805Buffer Access with Incorrect Length Value
Research Concepts1000
+ Relationship Notes

This probably overlaps other categories including zero-length issues.

+ Causal Nature

Implicit

+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
PLOVERLength Parameter Inconsistency
+ 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 Applicable_Platforms, Description, Name, Relationships, Observed_Example, Relationship_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2009-03-10CWE Content TeamMITREInternal
updated Description, Name
2009-12-28CWE Content TeamMITREInternal
updated Observed_Examples
2010-02-16CWE Content TeamMITREInternal
updated Description, Potential_Mitigations, Relationships
2010-12-13CWE Content TeamMITREInternal
updated Potential_Mitigations
2011-03-29CWE Content TeamMITREInternal
updated Demonstrative_Examples
2011-06-01CWE Content TeamMITREInternal
updated Common_Consequences
2011-06-27CWE Content TeamMITREInternal
updated Common_Consequences
2012-05-11CWE Content TeamMITREInternal
updated Observed_Examples, Relationships
2012-10-30CWE Content TeamMITREInternal
updated Potential_Mitigations
2013-07-17CWE Content TeamMITREInternal
updated Type
Previous Entry Names
Change DatePrevious Entry Name
2008-09-09Length Parameter Inconsistency
2009-03-10Failure to Handle Length Parameter Inconsistency
Page Last Updated: February 18, 2014