CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
89.3%
The remote Ubuntu 20.04 ESM host has packages installed that are affected by a vulnerability as referenced in the USN-5194-1 advisory.
Denis Kasak discovered that Olm was not verifying the length of input being processed by the olm_pk_decrypt module, which introduced a stack-based buffer overflow vulnerability to the library. An attacker could use this to cause a denial of service (application crash) or possibly execute arbitrary code.
Tenable has extracted the preceding description block directly from the Ubuntu security advisory.
Note that Nessus has not tested for this issue but has instead relied only on the application’s self-reported version number.
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-5194-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##
include('compat.inc');
if (description)
{
script_id(183525);
script_version("1.1");
script_set_attribute(attribute:"plugin_modification_date", value:"2024/08/27");
script_cve_id("CVE-2021-34813");
script_xref(name:"USN", value:"5194-1");
script_name(english:"Ubuntu 20.04 ESM : Olm vulnerability (USN-5194-1)");
script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing a security update.");
script_set_attribute(attribute:"description", value:
"The remote Ubuntu 20.04 ESM host has packages installed that are affected by a vulnerability as referenced in the
USN-5194-1 advisory.
Denis Kasak discovered that Olm was not verifying the length of input being processed by the
olm_pk_decrypt module, which introduced a stack-based buffer overflow vulnerability to the library. An
attacker could use this to cause a denial of service (application crash) or possibly execute arbitrary
code.
Tenable has extracted the preceding description block directly from the Ubuntu security advisory.
Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/notices/USN-5194-1");
script_set_attribute(attribute:"solution", value:
"Update the affected libolm-dev, libolm3 and / or python3-olm packages.");
script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/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-2021-34813");
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:"2021/06/16");
script_set_attribute(attribute:"patch_publication_date", value:"2021/12/15");
script_set_attribute(attribute:"plugin_publication_date", value:"2023/10/20");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:esm");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libolm-dev");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libolm3");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3-olm");
script_set_attribute(attribute:"generated_plugin", value:"current");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"Ubuntu Local Security Checks");
script_copyright(english:"Ubuntu Security Notice (C) 2023-2024 Canonical, Inc. / NASL script (C) 2023-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_dependencies("ssh_get_info.nasl", "ubuntu_pro_sub_detect.nasl");
script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");
exit(0);
}
include('debian_package.inc');
if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('20.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 20.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) 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$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);
var ubuntu_pro_detected = get_kb_item('Host/Ubuntu/Pro/Services/esm-apps');
ubuntu_pro_detected = !empty_or_null(ubuntu_pro_detected);
var pro_caveat_needed = FALSE;
var pkgs = [
{'osver': '20.04', 'pkgname': 'libolm-dev', 'pkgver': '3.1.3+dfsg-2ubuntu0.1~esm1', 'ubuntu_pro': TRUE},
{'osver': '20.04', 'pkgname': 'libolm3', 'pkgver': '3.1.3+dfsg-2ubuntu0.1~esm1', 'ubuntu_pro': TRUE},
{'osver': '20.04', 'pkgname': 'python3-olm', 'pkgver': '3.1.3+dfsg-2ubuntu0.1~esm1', 'ubuntu_pro': TRUE}
];
var flag = 0;
foreach var package_array ( pkgs ) {
var osver = NULL;
var pkgname = NULL;
var pkgver = NULL;
if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
var pro_required = NULL;
if (!empty_or_null(package_array['ubuntu_pro'])) pro_required = package_array['ubuntu_pro'];
if (osver && pkgname && pkgver) {
if (ubuntu_check(osver:osver, pkgname:pkgname, pkgver:pkgver)) {
flag++;
if (!ubuntu_pro_detected && !pro_caveat_needed) pro_caveat_needed = pro_required;
}
}
}
if (flag)
{
var extra = '';
if (pro_caveat_needed) {
extra += 'NOTE: This vulnerability check contains fixes that apply to packages only \n';
extra += 'available in Ubuntu ESM repositories. Access to these package security updates \n';
extra += 'require an Ubuntu Pro subscription.\n\n';
}
extra += ubuntu_report_get();
security_report_v4(
port : 0,
severity : SECURITY_HOLE,
extra : extra
);
exit(0);
}
else
{
var tested = ubuntu_pkg_tests_get();
if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'libolm-dev / libolm3 / python3-olm');
}
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
89.3%