Vulnerability CVE-2018-20187


Published: 2019-03-08   Modified: 2019-03-09

Description:
A side-channel issue was discovered in Botan before 2.9.0. An attacker capable of precisely measuring the time taken for ECC key generation may be able to derive information about the high bits of the secret key, as the function to derive the public point from the secret scalar uses an unblinded Montgomery ladder whose loop iteration count depends on the bitlength of the secret. This issue affects only key generation, not ECDSA signatures or ECDH key agreement.

Type:

CWE-320

(Key Management Errors)

CVSS2 => (AV:N/AC:M/Au:N/C:P/I:N/A:N)

CVSS Base Score
Impact Subscore
Exploitability Subscore
4.3/10
2.9/10
8.6/10
Exploit range
Attack complexity
Authentication
Remote
Medium
No required
Confidentiality impact
Integrity impact
Availability impact
Partial
None
None
Affected software
Botan project -> Botan 

 References:
https://botan.randombit.net/news.html
https://botan.randombit.net/security.html
https://github.com/crocs-muni/ECTester

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