#VU7299 Side-channel attack in Libgcrypt - CVE-2017-9526

Vulnerability identifier: #VU7299

Vulnerability risk: Low

CVSSv4.0: 1.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-9526

CWE-ID: CWE-310

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Libgcrypt
Client/Desktop applications / Encryption software

Vendor: GNU

Description
The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists in libgcrypt's EdDSA implementation. An attacker who learns the EdDSA session key (from side-channel observation during the signing process) can easily recover the long-term secret key.

Mitigation
Update to version 1.7.7.

Vulnerable software versions

Libgcrypt: 1.7.0 - 1.7.6

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External links
https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=f9494b3f258e01b6af8bd3941ce436bc...
https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=5a22de904a0a366ae79f03ff1e13a123...
https://bugzilla.suse.com/show_bug.cgi?id=1042326

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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.