CWE-943: Improper Neutralization of Special Elements in Data Query Logic
Weakness ID: 943
Vulnerability Mapping:
ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes) Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.
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Description
The product generates a query intended to access or manipulate data in a data store such as a database, but it does not neutralize or incorrectly neutralizes special elements that can modify the intended logic of the query.
Extended Description
Depending on the capabilities of the query language, an attacker could inject additional logic into the query to:
Modify the intended selection criteria, thus changing which data entities (e.g., records) are returned, modified, or otherwise manipulated
Append additional commands to the query
Return more entities than intended
Return fewer entities than intended
Cause entities to be sorted in an unexpected way
The ability to execute additional commands or change which entities are returned has obvious risks. But when the product logic depends on the order or number of entities, this can also lead to vulnerabilities. For example, if the query expects to return only one entity that specifies an administrative user, but an attacker can change which entities are returned, this could cause the logic to return information for a regular user and incorrectly assume that the user has administrative privileges.
While this weakness is most commonly associated with SQL injection, there are many other query languages that are also subject to injection attacks, including HTSQL, LDAP, DQL, XQuery, Xpath, and "NoSQL" languages.
Common Consequences
This table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.
Scope
Impact
Likelihood
Confidentiality Integrity Availability Access Control
This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.
Relevant to the view "Research Concepts" (CWE-1000)
Nature
Type
ID
Name
ChildOf
Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.
Relevant to the view "Architectural Concepts" (CWE-1008)
Nature
Type
ID
Name
MemberOf
Category - a CWE entry that contains a set of other entries that share a common characteristic.
The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.
Phase
Note
Implementation
REALIZATION: This weakness is caused during implementation of an architectural security tactic.
Applicable Platforms
This listing shows possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.
Languages
Class: Not Language-Specific (Undetermined Prevalence)
Demonstrative Examples
Example 1
The following code dynamically constructs and executes a SQL query that searches for items matching a specified name. The query restricts the items displayed to those where owner matches the user name of the currently-authenticated user.
(bad code)
Example Language: C#
... string userName = ctx.getAuthenticatedUserName(); string query = "SELECT * FROM items WHERE owner = '" + userName + "' AND itemname = '" + ItemName.Text + "'"; sda = new SqlDataAdapter(query, conn); DataTable dt = new DataTable(); sda.Fill(dt); ...
The query that this code intends to execute follows:
(informative)
SELECT * FROM items WHERE owner = <userName> AND itemname = <itemName>;
However, because the query is constructed dynamically by concatenating a constant base query string and a user input string, the query only behaves correctly if itemName does not contain a single-quote character. If an attacker with the user name wiley enters the string:
(attack code)
name' OR 'a'='a
for itemName, then the query becomes the following:
(attack code)
SELECT * FROM items WHERE owner = 'wiley' AND itemname = 'name' OR 'a'='a';
The addition of the:
(attack code)
OR 'a'='a
condition causes the WHERE clause to always evaluate to true, so the query becomes logically equivalent to the much simpler query:
(attack code)
SELECT * FROM items;
This simplification of the query allows the attacker to bypass the requirement that the query only return items owned by the authenticated user; the query now returns all entries stored in the items table, regardless of their specified owner.
Example 2
The code below constructs an LDAP query using user input address data:
Because the code fails to neutralize the address string used to construct the query, an attacker can supply an address that includes additional LDAP queries.
Example 3
Consider the following simple XML document that stores authentication information and a snippet of Java code that uses XPath query to retrieve authentication information:
Assume that user "john" wishes to leverage XPath Injection and login without a valid password. By providing a username "john" and password "' or ''='" the XPath expression now becomes
(attack code)
//users/user[login/text()='john' or ''='' and password/text() = '' or ''='']/home_dir/text()
This lets user "john" login without a valid password, thus bypassing authentication.
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
Effectiveness: High
Memberships
This MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.
Nature
Type
ID
Name
MemberOf
Category - a CWE entry that contains a set of other entries that share a common characteristic.
(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)
Reason: Abstraction
Rationale:
This CWE entry is a Class and might have Base-level children that would be more appropriate
Comments:
Examine children of this entry to see if there is a better fit
Notes
Relationship
It could be argued that data query languages are effectively a command language - albeit with a limited set of commands - and thus any query-language injection issue could be treated as a child of CWE-74. However, CWE-943 is intended to better organize query-oriented issues to separate them from fully-functioning programming languages, and also to provide a more precise identifier for the many query languages that do not have their own CWE identifier.
Description
This table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.
Relevant to the view "Architectural Concepts" (CWE-1008)
