Website data exfiltration via unescaped namespace URL
Published Jan 8, 2020 · Updated Aug 5, 2024
CSS injection in Mozilla Firefox before 72 and Firefox ESR before 68.4 allows remote attackers to exfiltrate site data through pasted content. During clipboard sanitization, the @namespace serializer wraps an attacker-controlled URL in quotes without escaping an embedded quote, enabling an injected @import rule. Exploitation requires a user to paste malicious clipboard content into a website with a rich text editor; injected CSS can read page tokens and transmit them to an attacker-controlled endpoint.
Summary
What happened
CSS injection in Mozilla Firefox before 72 and Firefox ESR before 68.4 allows remote attackers to exfiltrate site data through pasted content. During clipboard sanitization, the @namespace serializer wraps an attacker-controlled URL in quotes without escaping an embedded quote, enabling an injected @import rule. Exploitation requires a user to paste malicious clipboard content into a website with a rich text editor; injected CSS can read page tokens and transmit them to an attacker-controlled endpoint.
The record
- CVE
- CVE-2019-17016
- Published
- Jan 8, 2020
- Updated
- Aug 5, 2024
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- CWE-79, T1204.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 8, 2020CVE publishedPublication date reported by the CVE source.
- Aug 5, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=before 72
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- CSS @namespace sanitizer data-exfiltration proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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