SSRF via decimal parsing of octal IPv4 input
Published Apr 1, 2021 · Updated Aug 3, 2024
Improper input validation in netmask 1.0.6 and earlier allows remote attackers to bypass IP-based filters with octal IPv4 input. The ip2long parser validates each octet with decimal parseInt but leaves the original string for later bitwise conversion, causing leading-zero octets to differ from network-client interpretations. No authentication or user interaction is required; exposure exists when a dependent application passes attacker-controlled IP strings to netmask for access decisions, enabling requests to internal hosts.
Summary
What happened
Improper input validation in netmask 1.0.6 and earlier allows remote attackers to bypass IP-based filters with octal IPv4 input. The ip2long parser validates each octet with decimal parseInt but leaves the original string for later bitwise conversion, causing leading-zero octets to differ from network-client interpretations. No authentication or user interaction is required; exposure exists when a dependent application passes attacker-controlled IP strings to netmask for access decisions, enabling requests to internal hosts.
The record
- CVE
- CVE-2021-28918
- Published
- Apr 1, 2021
- Updated
- Aug 3, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-20, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 1, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
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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
- Octal IPv4 parsing proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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