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Zend-Mail remote code execution in zend-mail via Sendmail adapter

High severity GitHub Reviewed Published Jun 7, 2024 to the GitHub Advisory Database • Updated Jun 7, 2024

Package

composer zendframework/zend-mail (Composer)

Affected versions

>= 2.0.0, < 2.4.11
>= 2.5.0, < 2.7.2

Patched versions

2.4.11
2.7.2

Description

When using the zend-mail component to send email via the Zend\Mail\Transport\Sendmail transport, a malicious user may be able to inject arbitrary parameters to the system sendmail program. The attack is performed by providing additional quote characters within an address; when unsanitized, they can be interpreted as additional command line arguments, leading to the vulnerability.

The following example demonstrates injecting additional parameters to the sendmail binary via the From address:

use Zend\Mail;

$mail = new Mail\Message();
$mail->setBody('This is the text of the email.');

// inject additional parameters to sendmail command line
$mail->setFrom('"AAA\" params injection"@domain', 'Sender\'s name');

$mail->addTo('hacker@localhost', 'Name of recipient');
$mail->setSubject('TestSubject');

$transport = new Mail\Transport\Sendmail();
$transport->send($mail);

The attack works because zend-mail filters the email addresses using the RFC 3696 specification, where the string "AAA" params injection"@Domain is considered a valid address. This validation is provided using the zend-validator component with the following parameters:

Zend\Validator\EmailAddress(
    Zend\Validator\Hostname::ALLOW_DNS | Zend\Validator\Hostname::ALLOW_LOCAL
)

The above accepts local domain with any string specified by double quotes as the local part. While this is valid per RFC 3696, due to the fact that sender email addresses are provided to the sendmail binary via the command line, they create the vulnerability described above.

References

Published to the GitHub Advisory Database Jun 7, 2024
Reviewed Jun 7, 2024
Last updated Jun 7, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weaknesses

CVE ID

No known CVE

GHSA ID

GHSA-cxf7-m5g2-v594
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