CVE-2018-13389 in Confluence
Summary
by MITRE
The attachment resource in Atlassian Confluence before version 6.6.1 allows remote attackers to spoof web content in the Mozilla Firefox Browser through attachments that have a content-type of application/rdf+xml.
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Analysis
by VulDB Data Team • 03/01/2020
The vulnerability identified as CVE-2018-13389 resides within Atlassian Confluence's attachment handling mechanism, specifically affecting versions prior to 6.6.1. This security flaw enables remote attackers to manipulate web content presentation within the Mozilla Firefox browser environment through strategic manipulation of attachment metadata. The issue stems from insufficient validation of content-type headers when processing file attachments, creating a potential vector for cross-site scripting and content spoofing attacks.
The technical exploitation of this vulnerability occurs through the manipulation of the content-type field in attachment resources, specifically targeting the application/rdf+xml MIME type. When Firefox processes these attachments, the browser's rendering engine interprets the content based on the specified content-type, potentially executing malicious code or displaying misleading information. This flaw represents a classic case of improper input validation where the system fails to adequately sanitize or verify the content-type header before rendering the attachment. The vulnerability aligns with CWE-79, which addresses cross-site scripting vulnerabilities, and CWE-20, concerning improper input validation. Attackers can leverage this weakness to craft malicious attachments that appear legitimate but contain harmful content that gets executed in the victim's browser context.
The operational impact of CVE-2018-13389 extends beyond simple content spoofing, as it can facilitate more sophisticated attacks including phishing attempts, credential theft, and unauthorized access to sensitive information. In a corporate environment, this vulnerability could enable attackers to impersonate legitimate system administrators or internal resources, potentially leading to privilege escalation or data exfiltration. The attack surface is particularly concerning given Confluence's widespread use in enterprise settings for collaboration and documentation sharing, where users frequently interact with attachments containing sensitive business information. The vulnerability can be exploited through various attack vectors including email attachments, shared document repositories, or even through compromised Confluence instances that allow unauthorized file uploads.
Organizations should immediately implement mitigation strategies including updating to Atlassian Confluence version 6.6.1 or later, which includes proper content-type validation mechanisms. Additional protective measures involve implementing strict content filtering policies, monitoring attachment uploads for suspicious content-type headers, and educating users about the risks of opening untrusted attachments. Network-level protections such as web application firewalls can help detect and block malicious attachment requests. The vulnerability also highlights the importance of following ATT&CK framework principles for defensive measures, particularly focusing on privilege escalation and defense evasion techniques that attackers might employ through such content manipulation vulnerabilities. Security teams should conduct thorough audits of attachment handling processes and implement automated scanning for suspicious content-type values to prevent exploitation of similar weaknesses in other systems.