Attachment filter bypass via unescaped filename quotes
Published Jun 8, 2020 · Updated Aug 4, 2024
Output escaping in PHPMailer 6.1.5 and earlier allows attackers to bypass attachment filters via a quoted attachment name. Attachment methods such as addAttachment place an unescaped double quote into Content-Type and Content-Disposition filename parameters, causing parsers to ignore the trailing extension. Exploitation requires calling code to accept an attacker-influenced attachment name, and the bounded consequence is misclassification by receiving mail relays or filters.
Summary
What happened
Output escaping in PHPMailer 6.1.5 and earlier allows attackers to bypass attachment filters via a quoted attachment name. Attachment methods such as addAttachment place an unescaped double quote into Content-Type and Content-Disposition filename parameters, causing parsers to ignore the trailing extension. Exploitation requires calling code to accept an attacker-influenced attachment name, and the bounded consequence is misclassification by receiving mail relays or filters.
The record
- CVE
- CVE-2020-13625
- Published
- Jun 8, 2020
- Updated
- Aug 4, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-116, T1036
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 8, 2020CVE publishedPublication date reported by the CVE source.
- Aug 4, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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.
Public exploit references
- PHPMailer attachment-name filter-bypass reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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