CVE-2012-4023 in Pebble
Summary
by MITRE
CRLF injection vulnerability in Pebble before 2.6.4 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via unspecified vectors.
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Analysis
by VulDB Data Team • 02/23/2019
The CVE-2012-4023 vulnerability represents a critical CRLF injection flaw in Pebble blogging software versions prior to 2.6.4, which fundamentally compromises the integrity of HTTP responses and enables sophisticated attack vectors. This vulnerability falls under the CWE-113 category of Improper Neutralization of CRLF Sequences in HTTP Headers, making it a direct descendant of well-known HTTP response splitting vulnerabilities that have plagued web applications for decades. The flaw specifically resides in how the Pebble platform processes user input that gets embedded into HTTP headers without proper sanitization, creating an avenue for attackers to inject malicious CRLF sequences that can manipulate HTTP response structures.
The technical exploitation of this vulnerability occurs when an attacker can influence the content of HTTP headers through unsanitized input fields within the Pebble application. When the application fails to properly validate or escape user-supplied data before incorporating it into HTTP response headers, malicious actors can inject carriage return line feed sequences that break out of the intended header context. This allows attackers to inject additional HTTP headers or manipulate existing ones, effectively enabling HTTP response splitting attacks where they can control multiple HTTP responses within a single connection. The unspecified vectors mentioned in the description suggest that multiple input points within the application could potentially be exploited, including but not limited to user comments, blog post titles, or parameter values that get reflected in HTTP headers.
The operational impact of this vulnerability extends beyond simple header injection, as it creates a foundation for more sophisticated attacks including session hijacking, cross-site scripting exploitation, and cache poisoning. Attackers can leverage HTTP response splitting to inject malicious content that gets cached by proxies or browsers, potentially affecting multiple users who access the compromised application. The vulnerability particularly affects web applications that rely on Pebble for content management, making it a significant concern for organizations that depend on this blogging platform for their online presence. This type of vulnerability directly violates the principle of least privilege and proper input validation, as it allows untrusted input to influence the application's HTTP response generation process.
Security professionals should implement immediate mitigations including updating to Pebble version 2.6.4 or later, which contains the necessary patches to address the CRLF injection flaw. Additionally, organizations should deploy web application firewalls that can detect and block suspicious CRLF sequences in HTTP headers, and implement comprehensive input validation routines that sanitize all user-supplied data before it can influence HTTP response generation. The ATT&CK framework categorizes this vulnerability under T1190 - Proxying, as it enables attackers to manipulate HTTP responses through header injection techniques. Organizations should also consider implementing Content Security Policy headers and other defensive measures to limit the impact of potential exploitation, while ensuring that all input fields are properly escaped and validated against known malicious patterns. The vulnerability serves as a reminder of the critical importance of proper HTTP header sanitization in web applications and the necessity of regular security updates to protect against known vulnerabilities.