CAPEC-183: IMAP/SMTP Command Injection

Description
An adversary exploits weaknesses in input validation on web-mail servers to execute commands on the IMAP/SMTP server. Web-mail servers often sit between the Internet and the IMAP or SMTP mail server. User requests are received by the web-mail servers which then query the back-end mail server for the requested information and return this response to the user. In an IMAP/SMTP command injection attack, mail-server commands are embedded in parts of the request sent to the web-mail server. If the web-mail server fails to adequately sanitize these requests, these commands are then sent to the back-end mail server when it is queried by the web-mail server, where the commands are then executed. This attack can be especially dangerous since administrators may assume that the back-end server is protected against direct Internet access and therefore may not secure it adequately against the execution of malicious commands.
Extended Description

Most commonly, attackers would take advantage of controls that provided too little protection for sensitive activities in order to perform actions that should be denied to them. In some circumstances, an attacker may be able to take advantage of overly restrictive access control policies, initiating denial of services (if an application locks because it unexpectedly failed to be granted access) or causing other legitimate actions to fail due to security. The latter class of attacks, however, is usually less severe and easier to detect than attacks based on inadequate security restrictions. This attack pattern differs from CAPEC 1, "Accessing Functionality Not Properly Constrained by ACLs" in that the latter describes attacks where sensitive functionality lacks access controls, where, in this pattern, the access control is present, but incorrectly configured.

Severity :

Medium

Possibility :

Type :

Standard
Relationships with other CAPECs

This table shows the other attack patterns and high level categories that are related to this attack pattern.

CAPEC-248: Command Injection Command Injection
Prerequisites

This table shows the other attack patterns and high level categories that are related to this attack pattern.

  • The target environment must consist of a web-mail server that the attacker can query and a back-end mail server. The back-end mail server need not be directly accessible to the attacker.
  • The web-mail server must fail to adequately sanitize fields received from users and passed on to the back-end mail server.
  • The back-end mail server must not be adequately secured against receiving malicious commands from the web-mail server.
Skills required

This table shows the other attack patterns and high level categories that are related to this attack pattern.

Taxonomy mappings

Mappings to ATT&CK, OWASP and other frameworks.

Resources required

None: No specialized resources are required to execute this type of attack. However, in most cases, the attacker will need to be a recognized user of the web-mail server.

Related CWE

A Related Weakness relationship associates a weakness with this attack pattern. Each association implies a weakness that must exist for a given attack to be successful.

CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')

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