Arch Linux alert ASA-201707-1 (libgcrypt)

From:
    	     
 
Remi Gacogne <rgacogne@archlinux.org> 
To:
    	     
 
arch-security@archlinux.org 
Subject:
    	     
 
[arch-security] [ASA-201707-1] libgcrypt: private key recovery 
Date:
    	     
 
Mon, 3 Jul 2017 16:46:17 +0200
Message-ID:
    	     
 
<7d6b497e-c81d-2554-a4cc-daad4e75c03f@archlinux.org>
Arch Linux Security Advisory ASA-201707-1
=========================================

Severity: High
Date    : 2017-07-03
CVE-ID  : CVE-2017-7526
Package : libgcrypt
Type    : private key recovery
Remote  : No
Link    : https://security.archlinux.org/AVG-338

Summary
=======

The package libgcrypt before version 1.7.8-1 is vulnerable to private
key recovery.

Resolution
==========

Upgrade to 1.7.8-1.

# pacman -Syu "libgcrypt>=1.7.8-1"

The problem has been fixed upstream in version 1.7.8.

Workaround
==========

None.

Description
===========

The pattern of squarings and multiplications in left-to-right sliding
windows in libgcrypt <= 1.7.7 leaks significant information about
exponent bits, allowing for the very efficient recovery of a full
1024-bit RSA key.

Impact
======

A local attacker can use a side-channel attack to recover a secret
private key.

References
==========

https://eprint.iacr.org/2017/627
https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;...
https://security.archlinux.org/CVE-2017-7526