CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:N/I:N/A:C
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
Percentile
99.9%
An update for kernel is now available for Red Hat Enterprise Linux 6.6 Advanced Update Support.
Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.
The kernel packages contain the Linux kernel, the core of any Linux operating system.
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)
For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
Bug Fix(es) :
MDS mitigations not enabled on Intel Skylake CPUs (BZ#1713026)
[RHEL6] md_clear flag missing from /proc/cpuinfo (BZ#1713029)
RHEL6 kernel does not disable SMT with mds=full,nosmt (BZ#1713044)
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Red Hat Security Advisory RHSA-2019:1489. The text
# itself is copyright (C) Red Hat, Inc.
#
include('compat.inc');
if (description)
{
script_id(125976);
script_version("1.8");
script_set_attribute(attribute:"plugin_modification_date", value:"2022/12/05");
script_cve_id(
"CVE-2019-11477",
"CVE-2019-11478",
"CVE-2019-11479",
"CVE-2019-3896"
);
script_xref(name:"RHSA", value:"2019:1489");
script_xref(name:"CEA-ID", value:"CEA-2019-0456");
script_name(english:"RHEL 6 : kernel (RHSA-2019:1489) (SACK Panic) (SACK Slowness)");
script_set_attribute(attribute:"synopsis", value:
"The remote Red Hat host is missing one or more security updates.");
script_set_attribute(attribute:"description", value:
"An update for kernel is now available for Red Hat Enterprise Linux 6.6
Advanced Update Support.
Red Hat Product Security has rated this update as having a security
impact of Important. A Common Vulnerability Scoring System (CVSS) base
score, which gives a detailed severity rating, is available for each
vulnerability from the CVE link(s) in the References section.
The kernel packages contain the Linux kernel, the core of any Linux
operating system.
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)
For more details about the security issue(s), including the impact, a
CVSS score, acknowledgments, and other related information, refer to
the CVE page(s) listed in the References section.
Bug Fix(es) :
* MDS mitigations not enabled on Intel Skylake CPUs (BZ#1713026)
* [RHEL6] md_clear flag missing from /proc/cpuinfo (BZ#1713029)
* RHEL6 kernel does not disable SMT with mds=full,nosmt (BZ#1713044)");
script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/vulnerabilities/tcpsack");
script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2019:1489");
script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/cve-2019-3896");
script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/cve-2019-11477");
script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/cve-2019-11478");
script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/cve-2019-11479");
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:"in_the_news", value:"true");
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:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-abi-whitelists");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debug");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debug-debuginfo");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debug-devel");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debuginfo");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-debuginfo-common-x86_64");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-devel");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-doc");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-firmware");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:kernel-headers");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:perf");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:perf-debuginfo");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:python-perf");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:python-perf-debuginfo");
script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:6.6");
script_set_attribute(attribute:"generated_plugin", value:"current");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"Red Hat Local Security Checks");
script_copyright(english:"This script is Copyright (C) 2019-2022 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_dependencies("ssh_get_info.nasl", "linux_alt_patch_detect.nasl");
script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/cpu");
exit(0);
}
include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");
include("rpm.inc");
include("ksplice.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) || "Red Hat" >!< release) audit(AUDIT_OS_NOT, "Red Hat");
os_ver = pregmatch(pattern: "Red Hat Enterprise Linux.*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Red Hat");
os_ver = os_ver[1];
if (! preg(pattern:"^6\.6([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Red Hat 6.6", "Red Hat " + os_ver);
if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$" && "s390" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Red Hat", cpu);
if (get_one_kb_item("Host/ksplice/kernel-cves"))
{
rm_kb_item(name:"Host/uptrack-uname-r");
cve_list = make_list("CVE-2019-11477", "CVE-2019-11478", "CVE-2019-11479", "CVE-2019-3896");
if (ksplice_cves_check(cve_list))
{
audit(AUDIT_PATCH_INSTALLED, "KSplice hotfix for RHSA-2019:1489");
}
else
{
__rpm_report = ksplice_reporting_text();
}
}
yum_updateinfo = get_kb_item("Host/RedHat/yum-updateinfo");
if (!empty_or_null(yum_updateinfo))
{
rhsa = "RHSA-2019:1489";
yum_report = redhat_generate_yum_updateinfo_report(rhsa:rhsa);
if (!empty_or_null(yum_report))
{
security_report_v4(
port : 0,
severity : SECURITY_HOLE,
extra : yum_report
);
exit(0);
}
else
{
audit_message = "affected by Red Hat security advisory " + rhsa;
audit(AUDIT_OS_NOT, audit_message);
}
}
else
{
flag = 0;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"kernel-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", reference:"kernel-abi-whitelists-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"kernel-debug-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"kernel-debug-debuginfo-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"kernel-debug-devel-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"kernel-debuginfo-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"kernel-debuginfo-common-x86_64-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"kernel-devel-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", reference:"kernel-doc-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", reference:"kernel-firmware-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"kernel-headers-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"perf-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"perf-debuginfo-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"python-perf-2.6.32-504.79.3.el6")) flag++;
if (rpm_check(release:"RHEL6", sp:"6", cpu:"x86_64", reference:"python-perf-debuginfo-2.6.32-504.79.3.el6")) flag++;
if (flag)
{
security_report_v4(
port : 0,
severity : SECURITY_HOLE,
extra : rpm_report_get() + redhat_report_package_caveat()
);
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");
}
}
Vendor | Product | Version | CPE |
---|---|---|---|
redhat | enterprise_linux | kernel-abi-whitelists | p-cpe:/a:redhat:enterprise_linux:kernel-abi-whitelists |
redhat | enterprise_linux | python-perf-debuginfo | p-cpe:/a:redhat:enterprise_linux:python-perf-debuginfo |
redhat | enterprise_linux | kernel-headers | p-cpe:/a:redhat:enterprise_linux:kernel-headers |
redhat | enterprise_linux | kernel-firmware | p-cpe:/a:redhat:enterprise_linux:kernel-firmware |
redhat | enterprise_linux | kernel-devel | p-cpe:/a:redhat:enterprise_linux:kernel-devel |
redhat | enterprise_linux | 6.6 | cpe:/o:redhat:enterprise_linux:6.6 |
redhat | enterprise_linux | kernel-debug-devel | p-cpe:/a:redhat:enterprise_linux:kernel-debug-devel |
redhat | enterprise_linux | kernel-doc | p-cpe:/a:redhat:enterprise_linux:kernel-doc |
redhat | enterprise_linux | perf-debuginfo | p-cpe:/a:redhat:enterprise_linux:perf-debuginfo |
redhat | enterprise_linux | kernel-debuginfo | p-cpe:/a:redhat:enterprise_linux:kernel-debuginfo |
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11477
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11478
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11479
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-3896
access.redhat.com/errata/RHSA-2019:1489
access.redhat.com/security/cve/cve-2019-11477
access.redhat.com/security/cve/cve-2019-11478
access.redhat.com/security/cve/cve-2019-11479
access.redhat.com/security/cve/cve-2019-3896
access.redhat.com/security/vulnerabilities/tcpsack
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:N/I:N/A:C
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
Percentile
99.9%