During key agreement in a TLS handshake using a DH(E) based ciphersuite a malicious server can send a very large prime value to the client. This will cause the client to spend an unreasonably long period of time generating a key for this prime resulting in a hang until the client has finished. This could be exploited in a Denial Of Service attack.(CVE-2018-0732 )
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2018-1098.
#
include("compat.inc");
if (description)
{
script_id(118595);
script_version("1.2");
script_set_attribute(attribute:"plugin_modification_date", value:"2022/01/31");
script_cve_id("CVE-2018-0732");
script_xref(name:"ALAS", value:"2018-1098");
script_name(english:"Amazon Linux AMI : openssl (ALAS-2018-1098)");
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:
"During key agreement in a TLS handshake using a DH(E) based
ciphersuite a malicious server can send a very large prime value to
the client. This will cause the client to spend an unreasonably long
period of time generating a key for this prime resulting in a hang
until the client has finished. This could be exploited in a Denial Of
Service attack.(CVE-2018-0732 )"
);
script_set_attribute(
attribute:"see_also",
value:"https://alas.aws.amazon.com/ALAS-2018-1098.html"
);
script_set_attribute(
attribute:"solution",
value:"Run 'yum update openssl' to update your system."
);
script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/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:L/PR:N/UI:N/S:U/C:N/I:N/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-2018-0732");
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:amazon:linux:openssl");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-debuginfo");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-devel");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-perl");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-static");
script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
script_set_attribute(attribute:"vuln_publication_date", value:"2018/06/12");
script_set_attribute(attribute:"patch_publication_date", value:"2018/10/30");
script_set_attribute(attribute:"plugin_publication_date", value:"2018/11/02");
script_set_attribute(attribute:"generated_plugin", value:"current");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_copyright(english:"This script is Copyright (C) 2018-2022 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:"openssl-1.0.2k-13.111.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"openssl-debuginfo-1.0.2k-13.111.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"openssl-devel-1.0.2k-13.111.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"openssl-perl-1.0.2k-13.111.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"openssl-static-1.0.2k-13.111.amzn1")) flag++;
if (flag)
{
if (report_verbosity > 0) security_warning(port:0, extra:rpm_report_get());
else security_warning(0);
exit(0);
}
else
{
tested = pkg_tests_get();
if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
else audit(AUDIT_PACKAGE_NOT_INSTALLED, "openssl / openssl-debuginfo / openssl-devel / openssl-perl / etc");
}
Vendor | Product | Version | CPE |
---|---|---|---|
amazon | linux | openssl | p-cpe:/a:amazon:linux:openssl |
amazon | linux | openssl-debuginfo | p-cpe:/a:amazon:linux:openssl-debuginfo |
amazon | linux | openssl-devel | p-cpe:/a:amazon:linux:openssl-devel |
amazon | linux | openssl-perl | p-cpe:/a:amazon:linux:openssl-perl |
amazon | linux | openssl-static | p-cpe:/a:amazon:linux:openssl-static |
amazon | linux | cpe:/o:amazon:linux |