The version of cacti installed on the remote host is prior to 1.1.19-2.20. It is, therefore, affected by a vulnerability as referenced in the ALAS-2023-1675 advisory.
remote_agent.php
file. This file can be accessed without authentication. This function retrieves the IP address of the client via get_client_addr
and resolves this IP address to the corresponding hostname via gethostbyaddr
. After this, it is verified that an entry within the poller
table exists, where the hostname corresponds to the resolved hostname. If such an entry was found, the function returns true
and the client is authorized.get_client_addr
function. The function is defined in the file lib/functions.php
and checks serval $_SERVER
variables to determine the IP address of the client. The variables beginning with HTTP_
can be arbitrarily set by an attacker.poller
table with the hostname of the server running Cacti, an attacker can bypass the authentication e.g. by providing the header Forwarded-For: <TARGETIP>
. This way the function get_client_addr
returns the IP address of the server running Cacti. The following call to gethostbyaddr
will resolve this IP address to the hostname of the server, which will pass the poller
hostname check because of the default entry. After the authorization of the remote_agent.php
file is bypassed, an attacker can trigger different actions. One of these actions is called polldata
. The called function poll_for_data
retrieves a few request parameters and loads the corresponding poller_item
entries from the database. If the action
of a poller_item
equals POLLER_ACTION_SCRIPT_PHP
, the function proc_open
is used to execute a PHP script. The attacker-controlled parameter $poller_id
is retrieved via the function get_nfilter_request_var
, which allows arbitrary strings. This variable is later inserted into the string passed to proc_open
, which leads to a command injection vulnerability. By e.g. providing the poller_id=;id
the id
command is executed. In order to reach the vulnerable call, the attacker must provide a host_id
and local_data_id
, where the action
of the corresponding poller_item
is set to POLLER_ACTION_SCRIPT_PHP
. Both of these ids (host_id
and local_data_id
) can easily be bruteforced. The only requirement is that a poller_item
with an POLLER_ACTION_SCRIPT_PHP
action exists. This is very likely on a productive instance because this action is added by some predefined templates like Device - Uptime
or Device - Polling Time
. This command injection vulnerability allows an unauthenticated user to execute arbitrary commands if a poller_item
with the action
type POLLER_ACTION_SCRIPT_PHP
(2
) is configured. The authorization bypass should be prevented by not allowing an attacker to make get_client_addr
(file lib/functions.php
) return an arbitrary IP address. This could be done by not honoring the HTTP_...
$_SERVER
variables. If these should be kept for compatibility reasons it should at least be prevented to fake the IP address of the server running Cacti. This vulnerability has been addressed in both the 1.2.x and 1.3.x release branches with 1.2.23
being the first release containing the patch. (CVE-2022-46169)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 Amazon Linux AMI Security Advisory ALAS-2023-1675.
##
include('compat.inc');
if (description)
{
script_id(170545);
script_version("1.3");
script_set_attribute(attribute:"plugin_modification_date", value:"2023/09/06");
script_cve_id("CVE-2022-46169");
script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2023/03/09");
script_name(english:"Amazon Linux AMI : cacti (ALAS-2023-1675)");
script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux AMI host is missing a security update.");
script_set_attribute(attribute:"description", value:
"The version of cacti installed on the remote host is prior to 1.1.19-2.20. It is, therefore, affected by a vulnerability
as referenced in the ALAS-2023-1675 advisory.
- Cacti is an open source platform which provides a robust and extensible operational monitoring and fault
management framework for users. In affected versions a command injection vulnerability allows an
unauthenticated user to execute arbitrary code on a server running Cacti, if a specific data source was
selected for any monitored device. The vulnerability resides in the `remote_agent.php` file. This file can
be accessed without authentication. This function retrieves the IP address of the client via
`get_client_addr` and resolves this IP address to the corresponding hostname via `gethostbyaddr`. After
this, it is verified that an entry within the `poller` table exists, where the hostname corresponds to the
resolved hostname. If such an entry was found, the function returns `true` and the client is authorized.
This authorization can be bypassed due to the implementation of the `get_client_addr` function. The
function is defined in the file `lib/functions.php` and checks serval `$_SERVER` variables to determine
the IP address of the client. The variables beginning with `HTTP_` can be arbitrarily set by an attacker.
Since there is a default entry in the `poller` table with the hostname of the server running Cacti, an
attacker can bypass the authentication e.g. by providing the header `Forwarded-For: <TARGETIP>`. This way
the function `get_client_addr` returns the IP address of the server running Cacti. The following call to
`gethostbyaddr` will resolve this IP address to the hostname of the server, which will pass the `poller`
hostname check because of the default entry. After the authorization of the `remote_agent.php` file is
bypassed, an attacker can trigger different actions. One of these actions is called `polldata`. The called
function `poll_for_data` retrieves a few request parameters and loads the corresponding `poller_item`
entries from the database. If the `action` of a `poller_item` equals `POLLER_ACTION_SCRIPT_PHP`, the
function `proc_open` is used to execute a PHP script. The attacker-controlled parameter `$poller_id` is
retrieved via the function `get_nfilter_request_var`, which allows arbitrary strings. This variable is
later inserted into the string passed to `proc_open`, which leads to a command injection vulnerability. By
e.g. providing the `poller_id=;id` the `id` command is executed. In order to reach the vulnerable call,
the attacker must provide a `host_id` and `local_data_id`, where the `action` of the corresponding
`poller_item` is set to `POLLER_ACTION_SCRIPT_PHP`. Both of these ids (`host_id` and `local_data_id`) can
easily be bruteforced. The only requirement is that a `poller_item` with an `POLLER_ACTION_SCRIPT_PHP`
action exists. This is very likely on a productive instance because this action is added by some
predefined templates like `Device - Uptime` or `Device - Polling Time`. This command injection
vulnerability allows an unauthenticated user to execute arbitrary commands if a `poller_item` with the
`action` type `POLLER_ACTION_SCRIPT_PHP` (`2`) is configured. The authorization bypass should be prevented
by not allowing an attacker to make `get_client_addr` (file `lib/functions.php`) return an arbitrary IP
address. This could be done by not honoring the `HTTP_...` `$_SERVER` variables. If these should be kept
for compatibility reasons it should at least be prevented to fake the IP address of the server running
Cacti. This vulnerability has been addressed in both the 1.2.x and 1.3.x release branches with `1.2.23`
being the first release containing the patch. (CVE-2022-46169)
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://alas.aws.amazon.com/ALAS-2023-1675.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2022-46169.html");
script_set_attribute(attribute:"solution", value:
"Run 'yum update cacti' to update your system.");
script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
script_set_cvss_temporal_vector("CVSS2#E:H/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:H/RL:O/RC:C");
script_set_attribute(attribute:"cvss_score_source", value:"CVE-2022-46169");
script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
script_set_attribute(attribute:"exploit_available", value:"true");
script_set_attribute(attribute:"exploit_framework_core", value:"true");
script_set_attribute(attribute:"metasploit_name", value:'Cacti 1.2.22 unauthenticated command injection');
script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");
script_set_attribute(attribute:"vuln_publication_date", value:"2022/12/05");
script_set_attribute(attribute:"patch_publication_date", value:"2023/01/19");
script_set_attribute(attribute:"plugin_publication_date", value:"2023/01/24");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:cacti");
script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
script_set_attribute(attribute:"generated_plugin", value:"current");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"Amazon Linux Local Security Checks");
script_copyright(english:"This script is Copyright (C) 2023 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_dependencies("ssh_get_info.nasl");
script_require_keys("Host/local_checks_enabled", "Host/AmazonLinux/release", "Host/AmazonLinux/rpm-list");
exit(0);
}
include("rpm.inc");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var alas_release = get_kb_item("Host/AmazonLinux/release");
if (isnull(alas_release) || !strlen(alas_release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d+|-\d+)", string:alas_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);
var pkgs = [
{'reference':'cacti-1.1.19-2.20.amzn1', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE}
];
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 = 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 && (!exists_check || rpm_exists(release:_release, rpm:exists_check))) {
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, "cacti");
}