Debian DSA-3446-1 : openssh - security update

#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Debian Security Advisory DSA-3446. The text 
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(87934);
  script_version("2.13");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/01/11");

  script_cve_id("CVE-2016-0777", "CVE-2016-0778");
  script_xref(name:"DSA", value:"3446");

  script_name(english:"Debian DSA-3446-1 : openssh - security update");
  script_summary(english:"Checks dpkg output for the updated package");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Debian host is missing a security-related update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"The Qualys Security team discovered two vulnerabilities in the roaming
code of the OpenSSH client (an implementation of the SSH protocol
suite).

SSH roaming enables a client, in case an SSH connection breaks
unexpectedly, to resume it at a later time, provided the server also
supports it.

The OpenSSH server doesn't support roaming, but the OpenSSH client
supports it (even though it's not documented) and it's enabled by
default.

  - CVE-2016-0777
    An information leak (memory disclosure) can be exploited
    by a rogue SSH server to trick a client into leaking
    sensitive data from the client memory, including for
    example private keys.

  - CVE-2016-0778
    A buffer overflow (leading to file descriptor leak), can
    also be exploited by a rogue SSH server, but due to
    another bug in the code is possibly not exploitable, and
    only under certain conditions (not the default
    configuration), when using ProxyCommand, ForwardAgent or
    ForwardX11.

This security update completely disables the roaming code in the
OpenSSH client.

It is also possible to disable roaming by adding the (undocumented)
option 'UseRoaming no' to the global /etc/ssh/ssh_config file, or to
the user configuration in ~/.ssh/config, or by passing -oUseRoaming=no
on the command line.

Users with passphrase-less private keys, especially in non interactive
setups (automated jobs using ssh, scp, rsync+ssh etc.) are advised to
update their keys if they have connected to an SSH server they don't
trust.

More details about identifying an attack and mitigations will be
available in the Qualys Security Advisory."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=810984"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2016-0777"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2016-0778"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/wheezy/openssh"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/jessie/openssh"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.debian.org/security/2016/dsa-3446"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Upgrade the openssh packages.

For the oldstable distribution (wheezy), these problems have been
fixed in version 1:6.0p1-4+deb7u3.

For the stable distribution (jessie), these problems have been fixed
in version 1:6.7p1-5+deb8u1."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:S/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openssh");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:7.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:8.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2016/01/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/01/15");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2016-2021 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Debian Local Security Checks");

  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:"7.0", prefix:"openssh-client", reference:"1:6.0p1-4+deb7u3")) flag++;
if (deb_check(release:"7.0", prefix:"openssh-client-udeb", reference:"1:6.0p1-4+deb7u3")) flag++;
if (deb_check(release:"7.0", prefix:"openssh-server", reference:"1:6.0p1-4+deb7u3")) flag++;
if (deb_check(release:"7.0", prefix:"openssh-server-udeb", reference:"1:6.0p1-4+deb7u3")) flag++;
if (deb_check(release:"7.0", prefix:"ssh", reference:"1:6.0p1-4+deb7u3")) flag++;
if (deb_check(release:"7.0", prefix:"ssh-askpass-gnome", reference:"1:6.0p1-4+deb7u3")) flag++;
if (deb_check(release:"7.0", prefix:"ssh-krb5", reference:"1:6.0p1-4+deb7u3")) flag++;
if (deb_check(release:"8.0", prefix:"openssh-client", reference:"1:6.7p1-5+deb8u1")) flag++;
if (deb_check(release:"8.0", prefix:"openssh-client-udeb", reference:"1:6.7p1-5+deb8u1")) flag++;
if (deb_check(release:"8.0", prefix:"openssh-server", reference:"1:6.7p1-5+deb8u1")) flag++;
if (deb_check(release:"8.0", prefix:"openssh-server-udeb", reference:"1:6.7p1-5+deb8u1")) flag++;
if (deb_check(release:"8.0", prefix:"openssh-sftp-server", reference:"1:6.7p1-5+deb8u1")) flag++;
if (deb_check(release:"8.0", prefix:"ssh", reference:"1:6.7p1-5+deb8u1")) flag++;
if (deb_check(release:"8.0", prefix:"ssh-askpass-gnome", reference:"1:6.7p1-5+deb8u1")) flag++;
if (deb_check(release:"8.0", prefix:"ssh-krb5", reference:"1:6.7p1-5+deb8u1")) 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");