dbus as used in DBusServer, allows cookie spoofing because of symlink mishandling in the reference implementation of DBUS_COOKIE_SHA1 in the libdbus library. (This only affects the DBUS_COOKIE_SHA1 authentication mechanism.) A malicious client with write access to its own home directory could manipulate a ~/.dbus-keyrings symlink to cause a DBusServer with a different uid to read and write in unintended locations. In the worst case, this could result in the DBusServer reusing a cookie that is known to the malicious client, and treating that cookie as evidence that a subsequent client connection came from an attacker-chosen uid, allowing authentication bypass.
(CVE-2019-12749)
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2019-1246.
#
include("compat.inc");
if (description)
{
script_id(127074);
script_version("1.2");
script_cvs_date("Date: 2020/01/06");
script_cve_id("CVE-2019-12749");
script_xref(name:"ALAS", value:"2019-1246");
script_name(english:"Amazon Linux AMI : dbus (ALAS-2019-1246)");
script_summary(english:"Checks rpm output for the updated packages");
script_set_attribute(
attribute:"synopsis",
value:"The remote Amazon Linux AMI host is missing a security update."
);
script_set_attribute(
attribute:"description",
value:
"dbus as used in DBusServer, allows cookie spoofing because of symlink
mishandling in the reference implementation of DBUS_COOKIE_SHA1 in the
libdbus library. (This only affects the DBUS_COOKIE_SHA1
authentication mechanism.) A malicious client with write access to its
own home directory could manipulate a ~/.dbus-keyrings symlink to
cause a DBusServer with a different uid to read and write in
unintended locations. In the worst case, this could result in the
DBusServer reusing a cookie that is known to the malicious client, and
treating that cookie as evidence that a subsequent client connection
came from an attacker-chosen uid, allowing authentication bypass.
(CVE-2019-12749)"
);
script_set_attribute(
attribute:"see_also",
value:"https://alas.aws.amazon.com/ALAS-2019-1246.html"
);
script_set_attribute(
attribute:"solution",
value:"Run 'yum update dbus' to update your system."
);
script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:N");
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:N");
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:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:dbus");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:dbus-debuginfo");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:dbus-devel");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:dbus-doc");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:dbus-libs");
script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
script_set_attribute(attribute:"vuln_publication_date", value:"2019/06/11");
script_set_attribute(attribute:"patch_publication_date", value:"2019/07/25");
script_set_attribute(attribute:"plugin_publication_date", value:"2019/07/26");
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:"Amazon Linux Local Security Checks");
script_dependencies("ssh_get_info.nasl");
script_require_keys("Host/local_checks_enabled", "Host/AmazonLinux/release", "Host/AmazonLinux/rpm-list");
exit(0);
}
include("audit.inc");
include("global_settings.inc");
include("rpm.inc");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/AmazonLinux/release");
if (isnull(release) || !strlen(release)) audit(AUDIT_OS_NOT, "Amazon Linux");
os_ver = pregmatch(pattern: "^AL(A|\d)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "A")
{
if (os_ver == 'A') os_ver = 'AMI';
audit(AUDIT_OS_NOT, "Amazon Linux AMI", "Amazon Linux " + os_ver);
}
if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
flag = 0;
if (rpm_check(release:"ALA", reference:"dbus-1.6.12-14.29.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"dbus-debuginfo-1.6.12-14.29.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"dbus-devel-1.6.12-14.29.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"dbus-doc-1.6.12-14.29.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"dbus-libs-1.6.12-14.29.amzn1")) flag++;
if (flag)
{
if (report_verbosity > 0) security_note(port:0, extra:rpm_report_get());
else security_note(0);
exit(0);
}
else
{
tested = pkg_tests_get();
if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
else audit(AUDIT_PACKAGE_NOT_INSTALLED, "dbus / dbus-debuginfo / dbus-devel / dbus-doc / dbus-libs");
}
Vendor | Product | Version | CPE |
---|---|---|---|
amazon | linux | dbus | p-cpe:/a:amazon:linux:dbus |
amazon | linux | dbus-debuginfo | p-cpe:/a:amazon:linux:dbus-debuginfo |
amazon | linux | dbus-devel | p-cpe:/a:amazon:linux:dbus-devel |
amazon | linux | dbus-doc | p-cpe:/a:amazon:linux:dbus-doc |
amazon | linux | dbus-libs | p-cpe:/a:amazon:linux:dbus-libs |
amazon | linux | cpe:/o:amazon:linux |