Vulnerabilities > CVE-2019-3896

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text is (C) Scientific Linux.
#

include("compat.inc");

if (description)
{
  script_id(125980);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/02/24");

  script_cve_id("CVE-2019-11477", "CVE-2019-11478", "CVE-2019-11479", "CVE-2019-3896");

  script_name(english:"Scientific Linux Security Update : kernel on SL6.x i386/x86_64 (20190617) (SACK Panic) (SACK Slowness)");
  script_summary(english:"Checks rpm output for the updated packages");

  script_set_attribute(
    attribute:"synopsis", 
    value:
"The remote Scientific Linux host is missing one or more security
updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Security Fix(es) :

  - An integer overflow flaw was found in the way the Linux
    kernel's networking subsystem processed TCP Selective
    Acknowledgment (SACK) segments. While processing SACK
    segments, the Linux kernel's socket buffer (SKB) data
    structure becomes fragmented. Each fragment is about TCP
    maximum segment size (MSS) bytes. To efficiently process
    SACK blocks, the Linux kernel merges multiple fragmented
    SKBs into one, potentially overflowing the variable
    holding the number of segments. A remote attacker could
    use this flaw to crash the Linux kernel by sending a
    crafted sequence of SACK segments on a TCP connection
    with small value of TCP MSS, resulting in a denial of
    service (DoS). (CVE-2019-11477)

  - kernel: Double free in lib/idr.c (CVE-2019-3896)

  - Kernel: tcp: excessive resource consumption while
    processing SACK blocks allows remote denial of service
    (CVE-2019-11478)

  - Kernel: tcp: excessive resource consumption for TCP
    connections with low MSS allows remote denial of service
    (CVE-2019-11479)

Bug Fix(es) :

  - MDS mitigations not enabled on Intel Skylake CPUs

  - kernel does not disable SMT with mds=full,nosmt

  - md_clear flag missing from /proc/cpuinfo"
  );
  # https://listserv.fnal.gov/scripts/wa.exe?A2=ind1906&L=SCIENTIFIC-LINUX-ERRATA&P=1368
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?95793eee"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/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:"cvss_score_source", value:"CVE-2019-3896");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel-abi-whitelists");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel-debug-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel-debug-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel-debuginfo-common-i686");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel-debuginfo-common-x86_64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel-firmware");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:kernel-headers");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:perf-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:python-perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:python-perf-debuginfo");
  script_set_attribute(attribute:"cpe", value:"x-cpe:/o:fermilab:scientific_linux");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/06/19");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/06/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/06/18");
  script_set_attribute(attribute:"in_the_news", value:"true");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Scientific Linux Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/cpu", "Host/RedHat/release", "Host/RedHat/rpm-list");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");
include("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || "Scientific Linux " >!< release) audit(AUDIT_HOST_NOT, "running Scientific Linux");
os_ver = pregmatch(pattern: "Scientific Linux.*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Scientific Linux");
os_ver = os_ver[1];
if (! preg(pattern:"^6([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Scientific Linux 6.x", "Scientific Linux " + os_ver);
if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if (cpu >!< "x86_64" && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Scientific Linux", cpu);


flag = 0;
if (rpm_check(release:"SL6", reference:"kernel-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"kernel-abi-whitelists-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"kernel-debug-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"kernel-debug-debuginfo-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"kernel-debug-devel-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"kernel-debuginfo-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"kernel-debuginfo-common-i686-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", cpu:"x86_64", reference:"kernel-debuginfo-common-x86_64-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"kernel-devel-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"kernel-doc-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"kernel-firmware-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"kernel-headers-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"perf-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"perf-debuginfo-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"python-perf-2.6.32-754.15.3.el6")) flag++;
if (rpm_check(release:"SL6", reference:"python-perf-debuginfo-2.6.32-754.15.3.el6")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "kernel / kernel-abi-whitelists / kernel-debug / etc");
}