Permanent proxy denial via uninitialized UUPS implementation
Published Nov 12, 2021 · Updated Aug 4, 2024
Improper initialization in OpenZeppelin Contracts 4.1.0 through 4.3.1 allows remote attackers to permanently disable UUPS proxies. An uninitialized UUPS implementation lets attackers become upgrade administrators and invoke upgradeToAndCall directly, which delegate-calls attacker code that executes SELFDESTRUCT against the implementation. Any proxy backed by the destroyed implementation becomes unusable and cannot be upgraded, blocking access to assets held through it.
Summary
What happened
Improper initialization in OpenZeppelin Contracts 4.1.0 through 4.3.1 allows remote attackers to permanently disable UUPS proxies. An uninitialized UUPS implementation lets attackers become upgrade administrators and invoke upgradeToAndCall directly, which delegate-calls attacker code that executes SELFDESTRUCT against the implementation. Any proxy backed by the destroyed implementation becomes unusable and cannot be upgraded, blocking access to assets held through it.
The record
- CVE
- CVE-2021-41264
- Published
- Nov 12, 2021
- Updated
- Aug 4, 2024
- Vendor
- OpenZeppelin
- Product
- OpenZeppelin Contracts
- Classifications
- CWE-665, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 12, 2021CVE 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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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 4.1.0 < 4.3.2
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
- UUPS proxy bricking demonstrationproof of concept · demonstrated
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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