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)
Libgcrypt before 1.7.10 and 1.8.x before 1.8.3 allows a memory-cache side-channel attack on ECDSA signatures that can be mitigated through the use of blinding during the signing process in the
_gcry_ecc_ecdsa_sign function in cipher/ecc-ecdsa.c, aka the Return Of the Hidden Number Problem or ROHNP. To discover an ECDSA key, the attacker needs access to either the local machine or a different virtual machine on the same physical host.(CVE-2018-0495)
Constructed ASN.1 types with a recursive definition (such as can be found in PKCS7) could eventually exceed the stack given malicious input with excessive recursion. This could result in a Denial Of Service attack. There are no such structures used within SSL/TLS that come from untrusted sources so this is considered safe.(CVE-2018-0739)
While parsing an IPAddressFamily extension in an X.509 certificate, it is possible to do a one-byte overread. This would result in an incorrect text display of the certificate. This bug has been present since 2006.(CVE-2017-3735)
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALAS-2018-1102.
#
include("compat.inc");
if (description)
{
script_id(118833);
script_version("1.2");
script_set_attribute(attribute:"plugin_modification_date", value:"2021/04/14");
script_cve_id("CVE-2017-3735", "CVE-2018-0495", "CVE-2018-0732", "CVE-2018-0739");
script_xref(name:"ALAS", value:"2018-1102");
script_name(english:"Amazon Linux 2 : openssl (ALAS-2018-1102)");
script_summary(english:"Checks rpm output for the updated packages");
script_set_attribute(
attribute:"synopsis",
value:"The remote Amazon Linux 2 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)
Libgcrypt before 1.7.10 and 1.8.x before 1.8.3 allows a memory-cache
side-channel attack on ECDSA signatures that can be mitigated through
the use of blinding during the signing process in the
_gcry_ecc_ecdsa_sign function in cipher/ecc-ecdsa.c, aka the Return Of
the Hidden Number Problem or ROHNP. To discover an ECDSA key, the
attacker needs access to either the local machine or a different
virtual machine on the same physical host.(CVE-2018-0495)
Constructed ASN.1 types with a recursive definition (such as can be
found in PKCS7) could eventually exceed the stack given malicious
input with excessive recursion. This could result in a Denial Of
Service attack. There are no such structures used within SSL/TLS that
come from untrusted sources so this is considered safe.(CVE-2018-0739)
While parsing an IPAddressFamily extension in an X.509 certificate, it
is possible to do a one-byte overread. This would result in an
incorrect text display of the certificate. This bug has been present
since 2006.(CVE-2017-3735)"
);
script_set_attribute(
attribute:"see_also",
value:"https://alas.aws.amazon.com/AL2/ALAS-2018-1102.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:P/A:N");
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:L/A:N");
script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-3735");
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-libs");
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:2");
script_set_attribute(attribute:"vuln_publication_date", value:"2017/08/28");
script_set_attribute(attribute:"patch_publication_date", value:"2018/11/07");
script_set_attribute(attribute:"plugin_publication_date", value:"2018/11/09");
script_set_attribute(attribute:"generated_plugin", value:"current");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_copyright(english:"This script is Copyright (C) 2018-2021 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 != "2")
{
if (os_ver == 'A') os_ver = 'AMI';
audit(AUDIT_OS_NOT, "Amazon Linux 2", "Amazon Linux " + os_ver);
}
if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
flag = 0;
if (rpm_check(release:"AL2", reference:"openssl-1.0.2k-16.amzn2.0.1")) flag++;
if (rpm_check(release:"AL2", reference:"openssl-debuginfo-1.0.2k-16.amzn2.0.1")) flag++;
if (rpm_check(release:"AL2", reference:"openssl-devel-1.0.2k-16.amzn2.0.1")) flag++;
if (rpm_check(release:"AL2", reference:"openssl-libs-1.0.2k-16.amzn2.0.1")) flag++;
if (rpm_check(release:"AL2", reference:"openssl-perl-1.0.2k-16.amzn2.0.1")) flag++;
if (rpm_check(release:"AL2", reference:"openssl-static-1.0.2k-16.amzn2.0.1")) 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-libs / etc");
}