Access-control bypass via zero-prefixed IPv4 parsing
Published Mar 29, 2021 · Updated Aug 3, 2024
Incorrect IP-address parsing in Perl Net::Netmask before 2.0000 allows remote attackers to bypass IP-based access controls. The quad2int routine accepts multi-digit IPv4 octets beginning with zero and packs them as decimal bytes, while operating-system networking can interpret the same text as octal. Exploitation requires a consuming application to authorize requests from the module's parsed address while another network layer acts on the differently interpreted address.
Summary
What happened
Incorrect IP-address parsing in Perl Net::Netmask before 2.0000 allows remote attackers to bypass IP-based access controls. The quad2int routine accepts multi-digit IPv4 octets beginning with zero and packs them as decimal bytes, while operating-system networking can interpret the same text as octal. Exploitation requires a consuming application to authorize requests from the module's parsed address while another network layer acts on the differently interpreted address.
The record
- CVE
- CVE-2021-29424
- Published
- Mar 29, 2021
- Updated
- Aug 3, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-704
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 29, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 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?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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
- Net::Netmask leading-zero parsing demonstrationproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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