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CAPEC-21: Exploitation of Trusted Identifiers

Attack Pattern ID: 21
Abstraction: Meta
Status: Stable
Presentation Filter:
+ Description

An adversary guesses, obtains, or "rides" a trusted identifier (e.g. session ID, resource ID, cookie, etc.) to perform authorized actions under the guise of an authenticated user or service. Attacks leveraging trusted identifiers typically result in the adversary laterally moving within the local network, since users are often allowed to authenticate to systems/applications within the network using the same identifier. This allows the adversary to obtain sensitive data, download/install malware on the system, pose as a legitimate user for social engineering purposes, and more.

Attacks on trusted identifiers take advantage of the fact that some software accepts user input without verifying its authenticity. Many server side processes are vulnerable to these attacks because the server to server communications have not been analyzed from a security perspective or the processes "trust" other systems because they are behind a firewall. Similarly, servers that use easy to guess or spoofable schemes for representing digital identity can also be vulnerable. Such systems frequently use schemes without cryptography and digital signatures (or with broken cryptography). Identifiers may be guessed or obtained due to insufficient randomness, poor protection (passed/stored in the clear), lack of integrity (unsigned), or improper correlation with access control policy enforcement points. Exposed configuration and properties files that contain sensitive data may additionally provide an adversary with the information needed to obtain these identifiers. An adversary may also "ride" an identifier via a malicious link, as is the case in Cross Site Request Forgery (CSRF) attacks.

Regardless of the attack vector, successful spoofing and impersonation of trusted credentials can lead to an adversary breaking authentication, authorization, and audit controls with the target system or application.

+ Likelihood Of Attack

High

+ Typical Severity

High

+ Relationships
Section HelpThis table shows the other attack patterns and high level categories that are related to this attack pattern. These relationships are defined as ChildOf and ParentOf, and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as CanFollow, PeerOf, and CanAlsoBe are defined to show similar attack patterns that the user may want to explore.
NatureTypeIDName
ParentOfStandard Attack PatternStandard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.62Cross Site Request Forgery
ParentOfStandard Attack PatternStandard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.196Session Credential Falsification through Forging
ParentOfStandard Attack PatternStandard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.510SaaS User Request Forgery
ParentOfStandard Attack PatternStandard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.593Session Hijacking
PeerOfStandard Attack PatternStandard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.12Choosing Message Identifier
Section HelpThis table shows the views that this attack pattern belongs to and top level categories within that view.
+ Execution Flow
Explore
  1. Survey the application for Indicators of Susceptibility: Using a variety of methods, until one is found that applies to the target, the adversary probes for cookies, session tokens, or entry points that bypass identifiers altogether.

    Techniques
    Spider all available pages
    Attack known bad interfaces
    Search outward-facing configuration and properties files for identifiers.
Experiment
  1. Fetch samples: The adversary fetches many samples of identifiers. This may be through legitimate access (logging in, legitimate connections, etc.) or via systematic probing.

    Techniques
    An adversary makes many anonymous connections and records the session IDs assigned.
    An adversary makes authorized connections and records the session tokens or credentials issued.
    An adversary gains access to (legitimately or illegitimately) a nearby system (e.g., in the same operations network, DMZ, or local network) and makes a connection from it, attempting to gain the same privileges as a trusted system.
Exploit
  1. Impersonate: An adversary can use successful experiments or authentications to impersonate an authorized user or system or to laterally move within a system or application

  2. Spoofing: Malicious data can be injected into the target system or into a victim user's system by an adversary. The adversary can also pose as a legitimate user to perform social engineering attacks.

  3. Data Exfiltration: The adversary can obtain sensitive data contained within the system or application.

+ Prerequisites
Server software must rely on weak identifier proof and/or verification schemes.
Identifiers must have long lifetimes and potential for reusability.
Server software must allow concurrent sessions to exist.
+ Skills Required
[Level: Low]
To achieve a direct connection with the weak or non-existent server session access control, and pose as an authorized user
+ Resources Required
Ability to deploy software on network.
Ability to communicate synchronously or asynchronously with server.
+ Consequences
Section HelpThis table specifies different individual consequences associated with the attack pattern. The Scope identifies the security property that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in their attack. 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 pattern will be used to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.
ScopeImpactLikelihood
Confidentiality
Access Control
Authentication
Gain Privileges
Confidentiality
Read Data
Integrity
Modify Data
+ Mitigations
Design: utilize strong federated identity such as SAML to encrypt and sign identity tokens in transit.
Implementation: Use industry standards session key generation mechanisms that utilize high amount of entropy to generate the session key. Many standard web and application servers will perform this task on your behalf.
Implementation: If the identifier is used for authentication, such as in the so-called single sign on use cases, then ensure that it is protected at the same level of assurance as authentication tokens.
Implementation: If the web or application server supports it, then encrypting and/or signing the identifier (such as cookie) can protect the ID if intercepted.
Design: Use strong session identifiers that are protected in transit and at rest.
Implementation: Utilize a session timeout for all sessions, for example 20 minutes. If the user does not explicitly logout, the server terminates their session after this period of inactivity. If the user logs back in then a new session key is generated.
Implementation: Verify authenticity of all identifiers at runtime.
+ Example Instances

Thin client applications like web applications are particularly vulnerable to session ID attacks. Since the server has very little control over the client, but still must track sessions, data, and objects on the server side, cookies and other mechanisms have been used to pass the key to the session data between the client and server. When these session keys are compromised it is trivial for an adversary to impersonate a user's session in effect, have the same capabilities as the authorized user. There are two main ways for an adversary to exploit session IDs.

A brute force attack involves an adversary repeatedly attempting to query the system with a spoofed session header in the HTTP request. A web server that uses a short session ID can be easily spoofed by trying many possible combinations so the parameters session-ID= 1234 has few possible combinations, and an adversary can retry several hundred or thousand request with little to no issue on their side.

The second method is interception, where a tool such as wireshark is used to sniff the wire and pull off any unprotected session identifiers. The adversary can then use these variables and access the application.

For example, in a message queuing system that allows service requesters to post messages to its queue through an open channel (such as anonymous FTP), authorization is done through checking group or role membership contained in the posted message. However, there is no proof that the message itself, the information in the message (such group or role membership), or the process that wrote the message to the queue is authentic and authorized to do so.
+ Taxonomy Mappings
Relevant to the ATT&CK taxonomy mapping
Entry IDEntry Name
1134Access Token Manipulation
+ References
[REF-1] G. Hoglund and G. McGraw. "Exploiting Software: How to Break Code". Addison-Wesley. 2004-02.
+ Content History
Submissions
Submission DateSubmitterOrganization
2014-06-23CAPEC Content TeamThe MITRE Corporation
Modifications
Modification DateModifierOrganization
2015-11-09CAPEC Content TeamThe MITRE Corporation
Updated Related_Attack_Patterns
2020-07-30CAPEC Content TeamThe MITRE Corporation
Updated @Name, @Status, Consequences, Description, Example_Instances, Execution_Flow, Mitigations, Prerequisites, Resources_Required, Taxonomy_Mappings
2020-12-17CAPEC Content TeamThe MITRE Corporation
Updated Description, Example_Instances
2021-06-24CAPEC Content TeamThe MITRE Corporation
Updated Taxonomy_Mappings
Previous Entry Names
Change DatePrevious Entry Name
2015-11-09Exploitation of Session Variables, Resource IDs and other Trusted Credentials
2020-07-30Exploitation of Trusted Credentials
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Page Last Updated or Reviewed: December 17, 2020