CVE-2015-3154

Vulnerability

Description

CVE-2015-3154 is a CRLF injection vulnerability in the Zend\Mail (Zend_Mail) and Zend\Http components of the Zend Framework, affecting versions before 1.12.12, 2.x before 2.3.8, and 2.4.x before 2.4.1 [1]. The vulnerability arises because the framework failed to sanitize or validate email headers for carriage return (\r) and line feed (\n) sequences, allowing an attacker to inject arbitrary CRLF sequences into header values [2].

Exploitation

Method

An attacker can exploit this by providing a maliciously crafted header value containing CRLF sequences, such as in the subject line of an email. The injected CRLF sequence causes the email body to be split, allowing the attacker to insert arbitrary content, including HTML and iframes, into the message. For example, a subject containing "\r\nContent-Type: text/html; charset = \"iso-8859-1\"\r\n\r\n" would cause a mail server to interpret the HTML as the message body, bypassing the intended body [2]. The same class of attack also applies to HTTP headers via Zend\Http, enabling HTTP response splitting [1][2].

Impact

A successful attack can lead to HTTP response splitting and header injection, potentially enabling XSS (cross-site scripting), cache poisoning, or session hijacking. The attacker could manipulate email content or HTTP responses to deceive users, redirect them to malicious sites, or perform phishing attacks [1][2].

Mitigation

The Zend Framework team addressed the vulnerability by introducing new header validation and filtering classes in version 2 (Zend\Mail\Header\HeaderName, Zend\Mail\Header\HeaderValue, Zend\Http\Header\HeaderValue) that use static methods to validate and sanitize header values according to IETF specifications [2]. Users should upgrade to Zend Framework 1.12.12, 2.3.8, 2.4.1, or later. This CVE is not listed in CISA's Known Exploited Vulnerabilities (KEV) catalog [1].