#VU40297 Information disclosure in Randombit products - CVE-2016-2849

Vulnerability identifier: #VU40297

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2016-2849

CWE-ID: CWE-200

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Debian Linux
Operating systems & Components / Operating system
Fedora
Operating systems & Components / Operating system
Botan
Universal components / Libraries / Libraries used by multiple products

Vendor: Debian
Fedoraproject
Randombit

Description

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

Botan before 1.10.13 and 1.11.x before 1.11.29 do not use a constant-time algorithm to perform a modular inverse on the signature nonce k, which might allow remote attackers to obtain ECDSA secret keys via a timing side-channel attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Debian Linux: 8.0

Fedora: 24

Botan: 1.10.12 - 1.11.28, 8.0, 24

---

External links
https://botan.randombit.net/security.html
https://lists.fedoraproject.org/pipermail/package-announce/2016-May/183669.html
https://marc.info/?l=botan-devel&m=146185420505943&w=2
https://www.debian.org/security/2016/dsa-3565
https://security.gentoo.org/glsa/201701-23

---

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.