Debian DLA-2303-1 : libssh security update

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory DLA-2303-1. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(139246);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/02/27");

  script_cve_id("CVE-2020-16135");

  script_name(english:"Debian DLA-2303-1 : libssh security update");

  script_set_attribute(attribute:"synopsis", value:
"The remote Debian host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The code in src/sftpserver.c did not verify the validity of certain
pointers and expected them to be valid. A NULL pointer dereference
could have been occurred that typically causes a crash and thus a
denial of service.

For Debian 9 stretch, this problem has been fixed in version
0.7.3-2+deb9u3.

We recommend that you upgrade your libssh packages.

For the detailed security status of libssh please refer to its
security tracker page at:
https://security-tracker.debian.org/tracker/libssh

NOTE: Tenable Network Security has extracted the preceding description
block directly from the DLA security advisory. Tenable has attempted
to automatically clean and format it as much as possible without
introducing additional issues.");
  script_set_attribute(attribute:"see_also", value:"https://lists.debian.org/debian-lts-announce/2020/07/msg00034.html");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/stretch/libssh");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/source-package/libssh");
  script_set_attribute(attribute:"solution", value:
"Upgrade the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-16135");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/07/29");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/07/31");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/08/03");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libssh-4");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libssh-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libssh-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libssh-gcrypt-4");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libssh-gcrypt-dev");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:9.0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Debian Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2020-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/Debian/release", "Host/Debian/dpkg-l");

  exit(0);
}


include("audit.inc");
include("debian_package.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/Debian/release")) audit(AUDIT_OS_NOT, "Debian");
if (!get_kb_item("Host/Debian/dpkg-l")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;
if (deb_check(release:"9.0", prefix:"libssh-4", reference:"0.7.3-2+deb9u3")) flag++;
if (deb_check(release:"9.0", prefix:"libssh-dev", reference:"0.7.3-2+deb9u3")) flag++;
if (deb_check(release:"9.0", prefix:"libssh-doc", reference:"0.7.3-2+deb9u3")) flag++;
if (deb_check(release:"9.0", prefix:"libssh-gcrypt-4", reference:"0.7.3-2+deb9u3")) flag++;
if (deb_check(release:"9.0", prefix:"libssh-gcrypt-dev", reference:"0.7.3-2+deb9u3")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:deb_report_get());
  else security_warning(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");