Zabbix Server 'active checks' Command Injection

#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(105042);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/04/11");

  script_cve_id("CVE-2017-2824");
  script_bugtraq_id(98083);

  script_name(english:"Zabbix Server 'active checks' Command Injection");

  script_set_attribute(attribute:"synopsis", value:
"A network monitoring application running on the remote host is
affected by a remote command injection vulnerability.");
  script_set_attribute(attribute:"description", value:
"The Zabbix server running on the remote host is affected by a remote
command injection vulnerability due to the failure to sanitize the
input data involving an IP address that would go into the 'ip' field 
of the 'interface' table in the 'zabbix' database. An unauthenticated,
remote attacker can exploit this, via specially crafted packets, to
execute OS commands.

Note that Zabbix server is reportedly affected by additional
vulnerabilities; however, this plugin has not tested for these");
  script_set_attribute(attribute:"see_also", value:"https://support.zabbix.com/browse/ZBX-12075");
  script_set_attribute(attribute:"see_also", value:"https://www.zabbix.com/rn/rn3.2.7");
  script_set_attribute(attribute:"see_also", value:"https://www.zabbix.com/rn/rn3.0.10");
  script_set_attribute(attribute:"see_also", value:"https://www.zabbix.com/rn/rn2.2.19");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Zabbix version 3.4.0 / 3.2.7 / 3.0.10 / 2.2.19 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/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:H/PR:N/UI:N/S:U/C:H/I:H/A:H");
  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:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/07/18");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/07/18");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/06");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:zabbix:zabbix");
  script_set_attribute(attribute:"thorough_tests", value:"true");
  script_end_attributes();

  script_category(ACT_ATTACK);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2017-2022 Tenable Network Security, Inc.");

  script_dependencies("zabbix_server_detect.nasl");
  script_require_ports("Services/zabbix_server", 10051);

  exit(0);
}

include("global_settings.inc");
include("misc_func.inc");
include("dump.inc");
include("audit.inc");

port = get_service(svc:'zabbix_server', default: 10051, exit_on_fail:TRUE);

soc = open_sock_tcp(port);
if (!soc) audit(AUDIT_SOCK_FAIL, port);

# Specify both invalid 'host' and 'ip'
# Valid chars in 'host' are: '0-9a-zA-Z. _-'
invalid_host = '$' + SCRIPT_NAME + '$';
invalid_ip   = SCRIPT_NAME;

req ='{"request":"active checks", "host":"' + 
  invalid_host + '","ip":"' +
  invalid_ip + '"}';

send(socket:soc, data:req);
res = recv(socket:soc, length:256);

if (! isnull(res))
{
  if(res =~ '^ZBXD')
  {
    # Patched server checks 'ip' first before checking 'host'
    if ('not a valid IP address' >< res)
    {
      audit(AUDIT_LISTEN_NOT_VULN, 'Zabbix server', port); 
    }
    # Vulnerable server doesn't check 'ip'
    else if ('invalid host name' >< res)
    {
      security_report_v4(port: port, severity: SECURITY_WARNING);
    }
    else
    {
      audit(AUDIT_RESP_BAD, port, "an 'active checks' request. Unexpected response:" + '\n' + hexdump(ddata: res) + '\n');  
    }
  }
  else
  {
    audit(AUDIT_RESP_BAD, port, "an 'active checks' request: bad Zabbix protocol header");  
  }
}
else
{
  audit(AUDIT_RESP_NOT, port, "an 'active checks' request");  
}