Occupancy inference via repeated AES-CBC ciphertext
Published Sep 16, 2021 · Updated Sep 17, 2024
Information exposure in KADEN-VODOMĚRY PICOFLUX AiR in all known versions allows physically proximate attackers to infer water use via radio traffic. An 8-bit Wireless M-Bus access counter wraps after 256 messages and reuses the AES-CBC initialization vector, causing unchanged leading plaintext blocks to produce repeated ciphertext. An unauthenticated attacker within radio range needs only a Wireless M-Bus T1 reader to distinguish zero from nonzero consumption and infer household activity; message contents remain encrypted.
Summary
What happened
Information exposure in KADEN-VODOMĚRY PICOFLUX AiR in all known versions allows physically proximate attackers to infer water use via radio traffic. An 8-bit Wireless M-Bus access counter wraps after 256 messages and reuses the AES-CBC initialization vector, causing unchanged leading plaintext blocks to produce repeated ciphertext. An unauthenticated attacker within radio range needs only a Wireless M-Bus T1 reader to distinguish zero from nonzero consumption and infer household activity; message contents remain encrypted.
The record
- CVE
- CVE-2021-34576
- Published
- Sep 16, 2021
- Updated
- Sep 17, 2024
- Vendor
- KADEN-VODOMĚRY, s.r.o.
- Product
- PICOFLUX AiR
- Classifications
- CWE-203, T1040
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 16, 2021CVE publishedPublication date reported by the CVE source.
- Sep 17, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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- Affected versionversion=all
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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