Vulnerability identifier: #VU33132

Vulnerability risk: Medium

CVSSv3.1: 5.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-20187

CWE-ID: CWE-320

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Botan
Universal components / Libraries / Libraries used by multiple products

Vendor: Randombit

Description

The vulnerability allows a remote non-authenticated attacker to gain access to sensitive information.

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.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Botan: 2.0.0 - 2.8.0

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External links
http://botan.randombit.net/news.html
http://botan.randombit.net/security.html
http://github.com/crocs-muni/ECTester

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.