Debian: Security Advisory (DLA-602-1)

# SPDX-FileCopyrightText: 2023 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.1.1.2.2016.602");
  script_cve_id("CVE-2016-6313");
  script_tag(name:"creation_date", value:"2023-03-08 12:56:44 +0000 (Wed, 08 Mar 2023)");
  script_version("2024-02-02T05:06:10+0000");
  script_tag(name:"last_modification", value:"2024-02-02 05:06:10 +0000 (Fri, 02 Feb 2024)");
  script_tag(name:"cvss_base", value:"5.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:P/I:N/A:N");
  script_tag(name:"severity_vector", value:"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2016-12-16 20:06:24 +0000 (Fri, 16 Dec 2016)");

  script_name("Debian: Security Advisory (DLA-602-1)");
  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2023 Greenbone AG");
  script_family("Debian Local Security Checks");
  script_dependencies("gather-package-list.nasl");
  script_mandatory_keys("ssh/login/debian_linux", "ssh/login/packages", re:"ssh/login/release=DEB7");

  script_xref(name:"Advisory-ID", value:"DLA-602-1");
  script_xref(name:"URL", value:"https://www.debian.org/lts/security/2016/DLA-602-1");
  script_xref(name:"URL", value:"https://wiki.debian.org/LTS");

  script_tag(name:"summary", value:"The remote host is missing an update for the Debian 'gnupg' package(s) announced via the DLA-602-1 advisory.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable package version is present on the target host.");

  script_tag(name:"insight", value:"CVE-2016-6313

Felix Doerre and Vladimir Klebanov from the Karlsruhe Institute of Technology discovered a flaw in the mixing functions of GnuPG's random number generator. An attacker who obtains 4640 bits from the RNG can trivially predict the next 160 bits of output.

A first analysis on the impact of this bug for GnuPG shows that existing RSA keys are not weakened. For DSA and Elgamal keys it is also unlikely that the private key can be predicted from other public information.

Bypassing GnuPG key checking Weaknesses have been found in GnuPG signature validation that attackers could exploit thanks to especially forged public keys and under specific hardware-software conditions. While the underlying problem cannot be solved only by software, GnuPG has been strengthened, avoiding to rely on keyring signature caches when verifying keys. Potential specific attacks are not valid any more with the patch of GnuPG

Bypassing GnuPG key checking: Vrije Universiteit Amsterdam and Katholieke Universteit Leuven researchers discovered an attack method, known as Flip Feng Shui, that concerns flaws in GnuPG. Researchers found that under specific hardware-software conditions, attackers could bypass the GnuPG signature validation by using forged public keys. While the underlying problem cannot be solved only by software, GnuPG has been made more robust to avoid relying on keyring signature caches when verifying keys.

For Debian 7 Wheezy, these issues have been addressed in version 1.4.12-7+deb7u8.

We recommend that you upgrade your gnupg packages.

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: [link moved to references]");

  script_tag(name:"affected", value:"'gnupg' package(s) on Debian 7.");

  script_tag(name:"solution", value:"Please install the updated package(s).");

  script_tag(name:"solution_type", value:"VendorFix");
  script_tag(name:"qod_type", value:"package");

  exit(0);
}

include("revisions-lib.inc");
include("pkg-lib-deb.inc");

release = dpkg_get_ssh_release();
if(!release)
  exit(0);

res = "";
report = "";

if(release == "DEB7") {

  if(!isnull(res = isdpkgvuln(pkg:"gnupg", ver:"1.4.12-7+deb7u8", rls:"DEB7"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"gnupg-curl", ver:"1.4.12-7+deb7u8", rls:"DEB7"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"gnupg-udeb", ver:"1.4.12-7+deb7u8", rls:"DEB7"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"gpgv", ver:"1.4.12-7+deb7u8", rls:"DEB7"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"gpgv-udeb", ver:"1.4.12-7+deb7u8", rls:"DEB7"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"gpgv-win32", ver:"1.4.12-7+deb7u8", rls:"DEB7"))) {
    report += res;
  }

  if(report != "") {
    security_message(data:report);
  } else if(__pkg_match) {
    exit(99);
  }
  exit(0);
}

exit(0);