Access-control bypass via ambiguous IPv4 parsing
Published Aug 7, 2021 · Updated Aug 3, 2024
Improper IP-address parsing in Rust's standard library before 1.53.0 allows remote attackers to bypass IP-based access controls. The std::net parser accepts leading-zero IPv4 octets as decimal, while downstream components can interpret the same text as octal and reach a different address. Reachability depends on an application accepting attacker-controlled address text, validating it with Rust, and then passing the original string to another component.
Summary
What happened
Improper IP-address parsing in Rust's standard library before 1.53.0 allows remote attackers to bypass IP-based access controls. The std::net parser accepts leading-zero IPv4 octets as decimal, while downstream components can interpret the same text as octal and reach a different address. Reachability depends on an application accepting attacker-controlled address text, validating it with Rust, and then passing the original string to another component.
The record
- CVE
- CVE-2021-29922
- Published
- Aug 7, 2021
- Updated
- Aug 3, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 7, 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
- Leading-zero 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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