7.2 High
CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:C/I:C/A:C
7.8 High
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.2 High
AI Score
Confidence
High
0.0005 Low
EPSS
Percentile
17.2%
The remote Oracle Linux 7 host has a package installed that is affected by multiple vulnerabilities as referenced in the ELSA-2021-9087 advisory.
Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be exploited from within a user namespace, if, for example, unprivileged user namespaces were allowed. It was possible to have a file not readable by an unprivileged user to be copied to a mountpoint controlled by the user, like a removable device. This was introduced in kernel version 4.19 by commit d1d04ef (ovl:
stack file ops). This was fixed in kernel version 5.8 by commits 56230d9 (ovl: verify permissions in ovl_path_open()), 48bd024 (ovl: switch to mounter creds in readdir) and 05acefb (ovl: check permission to open real file). Additionally, commits 130fdbc (ovl: pass correct flags for opening real directory) and 292f902 (ovl: call secutiry hook in ovl_real_ioctl()) in kernel 5.8 might also be desired or necessary. These additional commits introduced a regression in overlay mounts within user namespaces which prevented access to files with ownership outside of the user namespace. This regression was mitigated by subsequent commit b6650da (ovl: do not fail because of O_NOATIMEi) in kernel 5.11. (CVE-2020-16120)
An issue was discovered in the Linux kernel through 5.10.11. PI futexes have a kernel stack use-after-free during fault handling, allowing local users to execute code in the kernel, aka CID-34b1a1ce1458.
(CVE-2021-3347)
nbd_add_socket in drivers/block/nbd.c in the Linux kernel through 5.10.12 has an ndb_queue_rq use-after- free that could be triggered by local attackers (with access to the nbd device) via an I/O request at a certain point during device setup, aka CID-b98e762e3d71. (CVE-2021-3348)
Note that Nessus has not tested for these issues but has instead relied only on the application’s self-reported version number.
#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2021-9087.
##
include('deprecated_nasl_level.inc');
include('compat.inc');
if (description)
{
script_id(147205);
script_version("1.6");
script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/16");
script_cve_id("CVE-2020-16120", "CVE-2021-3347", "CVE-2021-3348");
script_name(english:"Oracle Linux 7 : Unbreakable Enterprise kernel-container (ELSA-2021-9087)");
script_set_attribute(attribute:"synopsis", value:
"The remote Oracle Linux host is missing one or more security updates.");
script_set_attribute(attribute:"description", value:
"The remote Oracle Linux 7 host has a package installed that is affected by multiple vulnerabilities as referenced in the
ELSA-2021-9087 advisory.
- Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be
exploited from within a user namespace, if, for example, unprivileged user namespaces were allowed. It was
possible to have a file not readable by an unprivileged user to be copied to a mountpoint controlled by
the user, like a removable device. This was introduced in kernel version 4.19 by commit d1d04ef (ovl:
stack file ops). This was fixed in kernel version 5.8 by commits 56230d9 (ovl: verify permissions in
ovl_path_open()), 48bd024 (ovl: switch to mounter creds in readdir) and 05acefb (ovl: check permission
to open real file). Additionally, commits 130fdbc (ovl: pass correct flags for opening real directory)
and 292f902 (ovl: call secutiry hook in ovl_real_ioctl()) in kernel 5.8 might also be desired or
necessary. These additional commits introduced a regression in overlay mounts within user namespaces which
prevented access to files with ownership outside of the user namespace. This regression was mitigated by
subsequent commit b6650da (ovl: do not fail because of O_NOATIMEi) in kernel 5.11. (CVE-2020-16120)
- An issue was discovered in the Linux kernel through 5.10.11. PI futexes have a kernel stack use-after-free
during fault handling, allowing local users to execute code in the kernel, aka CID-34b1a1ce1458.
(CVE-2021-3347)
- nbd_add_socket in drivers/block/nbd.c in the Linux kernel through 5.10.12 has an ndb_queue_rq use-after-
free that could be triggered by local attackers (with access to the nbd device) via an I/O request at a
certain point during device setup, aka CID-b98e762e3d71. (CVE-2021-3348)
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
script_set_attribute(attribute:"see_also", value:"https://linux.oracle.com/errata/ELSA-2021-9087.html");
script_set_attribute(attribute:"solution", value:
"Update the affected kernel-uek-container package.");
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:POC/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:P/RL:O/RC:C");
script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-3347");
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:"2020/10/16");
script_set_attribute(attribute:"patch_publication_date", value:"2021/03/09");
script_set_attribute(attribute:"plugin_publication_date", value:"2021/03/09");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:7");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-container");
script_set_attribute(attribute:"generated_plugin", value:"current");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"Oracle Linux Local Security Checks");
script_copyright(english:"This script is Copyright (C) 2021-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_dependencies("linux_alt_patch_detect.nasl", "ssh_get_info.nasl");
script_require_keys("Host/OracleLinux", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/local_checks_enabled");
exit(0);
}
include('ksplice.inc');
include('rpm.inc');
if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item('Host/OracleLinux')) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_release = get_kb_item("Host/RedHat/release");
if (isnull(os_release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:os_release)) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
os_ver = os_ver[1];
if (! preg(pattern:"^7([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 7', 'Oracle Linux ' + os_ver);
if (!get_kb_item('Host/RedHat/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);
var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Oracle Linux', cpu);
if ('x86_64' >!< cpu) audit(AUDIT_ARCH_NOT, 'x86_64', cpu);
var machine_uptrack_level = get_one_kb_item('Host/uptrack-uname-r');
if (machine_uptrack_level)
{
var trimmed_uptrack_level = ereg_replace(string:machine_uptrack_level, pattern:"\.(x86_64|i[3-6]86|aarch64)$", replace:'');
var fixed_uptrack_levels = ['4.14.35-2047.501.0.el7'];
foreach var fixed_uptrack_level ( fixed_uptrack_levels ) {
if (rpm_spec_vers_cmp(a:trimmed_uptrack_level, b:fixed_uptrack_level) >= 0)
{
audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for ELSA-2021-9087');
}
}
__rpm_report = 'Running KSplice level of ' + trimmed_uptrack_level + ' does not meet the minimum fixed level of ' + join(fixed_uptrack_levels, sep:' / ') + ' for this advisory.\n\n';
}
var kernel_major_minor = get_kb_item('Host/uname/major_minor');
if (empty_or_null(kernel_major_minor)) exit(1, 'Unable to determine kernel major-minor level.');
var expected_kernel_major_minor = '4.14';
if (kernel_major_minor != expected_kernel_major_minor)
audit(AUDIT_OS_NOT, 'running kernel level ' + expected_kernel_major_minor + ', it is running kernel level ' + kernel_major_minor);
var pkgs = [
{'reference':'kernel-uek-container-4.14.35-2047.501.0.el7', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-container-4.14.35'}
];
var flag = 0;
foreach var package_array ( pkgs ) {
var reference = NULL;
var _release = NULL;
var sp = NULL;
var _cpu = NULL;
var el_string = NULL;
var rpm_spec_vers_cmp = NULL;
var epoch = NULL;
var allowmaj = NULL;
var exists_check = NULL;
if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
if (!empty_or_null(package_array['release'])) _release = 'EL' + package_array['release'];
if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
if (!empty_or_null(package_array['cpu'])) _cpu = package_array['cpu'];
if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
if (reference && _release) {
if (exists_check) {
if (rpm_exists(release:_release, rpm:exists_check) && rpm_check(release:_release, sp:sp, cpu:cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
} else {
if (rpm_check(release:_release, sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
}
}
}
if (flag)
{
security_report_v4(
port : 0,
severity : SECURITY_HOLE,
extra : rpm_report_get()
);
exit(0);
}
else
{
var tested = pkg_tests_get();
if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'kernel-uek-container');
}
7.2 High
CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:C/I:C/A:C
7.8 High
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.2 High
AI Score
Confidence
High
0.0005 Low
EPSS
Percentile
17.2%