Vulnerability identifier: #VU33822

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-2015-0837

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
GnuPG
Client/Desktop applications / Encryption software

Vendor: GNU

Description

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

The mpi_powm function in Libgcrypt before 1.6.3 and GnuPG before 1.4.19 allows attackers to obtain sensitive information by leveraging timing differences when accessing a pre-computed table during modular exponentiation, related to a "Last-Level Cache Side-Channel Attack."

Mitigation
Install update from vendor's website.

Vulnerable software versions

GnuPG: 1.4.0 - 1.4.18

---

External links
http://www.debian.org/security/2015/dsa-3184
http://www.debian.org/security/2015/dsa-3185
http://ieeexplore.ieee.org/document/7163050
http://lists.gnupg.org/pipermail/gnupg-announce/2015q1/000363.html
http://lists.gnupg.org/pipermail/gnupg-announce/2015q1/000364.html

---

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.