Client crash via unchecked authenticated message length
Published Mar 4, 2021 · Updated Aug 3, 2024
Out-of-bounds reads in Yubico yubihsm-shell 2.0.3 and earlier allow attackers to crash client processes via authenticated device replies. _send_secure_msg() accepts an authenticated response whose embedded length becomes zero after MAC and session-ID subtraction, then aes_remove_padding() reads backward past the decrypted buffer. Exploitation requires a malicious HSM with session secrets or man-in-the-middle attackers able to modify traffic and generate a valid MAC; success interrupts the client with a segmentation fault.
Summary
What happened
Out-of-bounds reads in Yubico yubihsm-shell 2.0.3 and earlier allow attackers to crash client processes via authenticated device replies. _send_secure_msg() accepts an authenticated response whose embedded length becomes zero after MAC and session-ID subtraction, then aes_remove_padding() reads backward past the decrypted buffer. Exploitation requires a malicious HSM with session secrets or man-in-the-middle attackers able to modify traffic and generate a valid MAC; success interrupts the client with a segmentation fault.
The record
- CVE
- CVE-2021-27217
- Published
- Mar 4, 2021
- Updated
- Aug 3, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-125, T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 4, 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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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.
Public exploit references
- CVE-2021-27217 simulation patchproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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