CVE-2017-1000054 in Rocket.Chat
Summary
by MITRE
Rocket.Chat version 0.8.0 and newer is vulnerable to XSS in the markdown link parsing code for messages.
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Analysis
by VulDB Data Team • 10/26/2019
The vulnerability identified as CVE-2017-1000054 affects Rocket.Chat messaging platform versions 0.8.0 and later, presenting a cross-site scripting vulnerability within the markdown link parsing functionality. This issue arises from insufficient input validation and sanitization when processing markdown formatted links in chat messages, creating a potential attack vector for malicious actors to execute arbitrary code within the context of a victim's browser session. The vulnerability specifically targets the message processing pipeline where markdown syntax is converted to HTML, allowing attackers to inject malicious scripts through carefully crafted link structures that bypass normal security controls.
The technical flaw manifests in the markdown parser's handling of link elements, where user-provided content containing malicious script tags or javascript protocols is not properly escaped or validated before being rendered as HTML. When a user creates a message containing a markdown link with malicious content, the parser processes the link without adequate sanitization, potentially allowing script execution when other users view the message. This represents a classic cross-site scripting vulnerability classified under CWE-79, which specifically addresses the improper neutralization of input during web page generation. The vulnerability operates at the application layer and can be exploited through user interaction with maliciously crafted messages, making it particularly dangerous in collaborative environments where users frequently exchange information.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to steal session cookies, perform actions on behalf of users, redirect them to malicious sites, or even exfiltrate sensitive data from the chat environment. In enterprise settings where Rocket.Chat is used for internal communications, this vulnerability could allow attackers to escalate privileges, access confidential discussions, or compromise entire user sessions. The attack requires minimal user interaction beyond viewing the malicious message, making it particularly effective in environments with high message volume where users may not carefully inspect all content. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as it enables execution of malicious code through script injection.
Mitigation strategies for CVE-2017-1000054 should include immediate patching of Rocket.Chat installations to versions that properly sanitize markdown link inputs and implement comprehensive input validation. Organizations should also deploy content security policies to prevent script execution in chat environments, implement proper markdown sanitization libraries, and consider additional measures such as message content filtering and user behavior monitoring. Regular security assessments of web application components, particularly those handling user-generated content, are essential to identify similar vulnerabilities in other applications. The remediation process should also include user education regarding the risks of interacting with untrusted content and the importance of keeping software updated to address known vulnerabilities.