| Name |
Choosing Message Identifier |
|
| Likelyhood of attack |
Typical severity |
| High |
High |
|
| Summary |
This pattern of attack is defined by the selection of messages distributed over via multicast or public information channels that are intended for another client by determining the parameter value assigned to that client. This attack allows the adversary to gain access to potentially privileged information, and to possibly perpetrate other attacks through the distribution means by impersonation. If the channel/message being manipulated is an input rather than output mechanism for the system, (such as a command bus), this style of attack could be used to change the adversary's identifier to more a privileged one. |
| Prerequisites |
Information and client-sensitive (and client-specific) data must be present through a distribution channel available to all users. Distribution means must code (through channel, message identifiers, or convention) message destination in a manner visible within the distribution means itself (such as a control channel) or in the messages themselves. |
| Execution Flow |
| Step |
Phase |
Description |
Techniques |
| 1 |
Explore |
Determine the nature of messages being transported as well as the identifiers to be used as part of the attack |
|
| 2 |
Experiment |
If required, authenticate to the distribution channel |
|
| 3 |
Experiment |
If any particular client's information is available through the transport means simply by selecting a particular identifier, an attacker can simply provide that particular identifier. |
|
| 4 |
Experiment |
Attackers with client access connecting to output channels could change their channel identifier and see someone else's (perhaps more privileged) data. |
|
|
| Solutions | The purpose is to architect the system in a way that associates proper authentication/authorization with each channel/message. Re-architect system input/output channels as appropriate to distribute self-protecting data. That is, encrypt (or otherwise protect) channels/messages so that only authorized readers can see them. |
| Related Weaknesses |
|
CWE ID
|
Description
|
| CWE-201 |
Insertion of Sensitive Information Into Sent Data |
| CWE-306 |
Missing Authentication for Critical Function |
|
| Related CAPECS |
|
CAPEC ID
|
Description
|
| CAPEC-21 |
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. |
| CAPEC-216 |
An adversary manipulates a setting or parameter on communications channel in order to compromise its security. This can result in information exposure, insertion/removal of information from the communications stream, and/or potentially system compromise. |
|