CWE-1004: Sensitive Cookie Without 'HttpOnly' Flag
Weakness ID: 1004
Vulnerability Mapping:ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities Abstraction:
VariantVariant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.
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Description
The product uses a cookie to store sensitive information, but the cookie is not marked with the HttpOnly flag.
Extended Description
The HttpOnly flag directs compatible browsers to prevent client-side script from accessing cookies. Including the HttpOnly flag in the Set-Cookie HTTP response header helps mitigate the risk associated with Cross-Site Scripting (XSS) where an attacker's script code might attempt to read the contents of a cookie and exfiltrate information obtained. When set, browsers that support the flag will not reveal the contents of the cookie to a third party via client-side script executed via XSS.
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
Technical Impact: Read Application Data
If the HttpOnly flag is not set, then sensitive information stored in the cookie may be exposed to unintended parties.
Integrity
Technical Impact: Gain Privileges or Assume Identity
If the cookie in question is an authentication cookie, then not setting the HttpOnly flag may allow an adversary to steal authentication data (e.g., a session ID) and assume the identity of the user.
Potential Mitigations
Phase: Implementation
Leverage the HttpOnly flag when setting a sensitive cookie in a response.
Effectiveness: High
Note:
While this mitigation is effective for protecting cookies from a browser's own scripting engine, third-party components or plugins may have their own engines that allow access to cookies. Attackers might also be able to use XMLHTTPResponse to read the headers directly and obtain the cookie.
Relationships
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.
An HTTP cookie is a small piece of data attributed to a specific website and stored on the user's computer by the user's web browser. This data can be leveraged for a variety of purposes including saving information entered into form fields, recording user activity, and for authentication purposes. Cookies used to save or record information generated by the user are accessed and modified by script code embedded in a web page. While cookies used for authentication are created by the website's server and sent to the user to be attached to future requests. These authentication cookies are often not meant to be accessed by the web page sent to the user, and are instead just supposed to be attached to future requests to verify authentication details.
Modes
Of Introduction
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
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)
Technologies
Class: Web Based
(Undetermined Prevalence)
Likelihood Of Exploit
Medium
Demonstrative Examples
Example 1
In this example, a cookie is used to store a session ID for a client's interaction with a website. The intention is that the cookie will be sent to the website with each request made by the client.
The snippet of code below establishes a new cookie to hold the sessionID.
(bad code)
Example Language: Java
String sessionID = generateSessionId(); Cookie c = new Cookie("session_id", sessionID); response.addCookie(c);
The HttpOnly flag is not set for the cookie. An attacker who can perform XSS could insert malicious script such as:
When the client loads and executes this script, it makes a request to the attacker-controlled web site. The attacker can then log the request and steal the cookie.
To mitigate the risk, use the setHttpOnly(true) method.
(good code)
Example Language: Java
String sessionID = generateSessionId(); Cookie c = new Cookie("session_id", sessionID); c.setHttpOnly(true); response.addCookie(c);
Web application for a room automation system has client-side Javascript that sets a sensitive cookie without the HTTPOnly security attribute, allowing the cookie to be accessed.
CMS written in Python does not include the HTTPOnly flag in a Set-Cookie header, allowing remote attackers to obtain potentially sensitive information via script access to this cookie.
Appliance for managing encrypted communications does not use HttpOnly flag.
Detection
Methods
Automated Static Analysis
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 may be used to map to real-world vulnerabilities)
Reason:
Acceptable-Use
Rationale:
This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comments:
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.
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.
