Anti-spam bypass via spoofed client-IP headers
Published Mar 27, 2023 · Updated Feb 19, 2025
IP spoofing in Strategy11 LLC Formidable Forms before 6.1 allows remote attackers to bypass anti-spam protections via crafted headers. FrmAppHelper::get_ip_address trusts client-controlled forwarding and proxy headers when selecting the address recorded for a form submission. No authentication or user interaction is required, and the false address can misattribute entries and evade IP-based spam checks.
Summary
What happened
IP spoofing in Strategy11 LLC Formidable Forms before 6.1 allows remote attackers to bypass anti-spam protections via crafted headers. FrmAppHelper::get_ip_address trusts client-controlled forwarding and proxy headers when selecting the address recorded for a form submission. No authentication or user interaction is required, and the false address can misattribute entries and evade IP-based spam checks.
The record
- CVE
- CVE-2023-0816
- Published
- Mar 27, 2023
- Updated
- Feb 19, 2025
- Vendor
- Business Directory Team
- Product
- Formidable Forms
- Classifications
- CWE-290, T1036
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 27, 2023CVE publishedPublication date reported by the CVE source.
- Feb 19, 2025Record 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=0 <6.1
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.
Public exploit references
- WPScan crafted-header proof of conceptproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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