Microsoft Windows Server 2003 IIS 6.0 WebDAV PROPFIND Request Handling RCE (EXPLODINGCAN)

#
# (C) Tenable Network Security, Inc.
#

include('compat.inc');

if (description)
{
  script_id(99523);
  script_version("1.12");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/04/25");

  script_cve_id("CVE-2017-7269");
  script_bugtraq_id(97127);
  script_xref(name:"EDB-ID", value:"41738");
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2022/05/03");

  script_name(english:"Microsoft Windows Server 2003 IIS 6.0 WebDAV PROPFIND Request Handling RCE (EXPLODINGCAN)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Windows host is affected by a remote code execution
vulnerability.");
  script_set_attribute(attribute:"description", value:
"The remote host is running Windows Server 2003 and Internet
Information Services (IIS) 6.0 with WebDAV enabled. It is, therefore,
affected by a buffer overflow condition in the IIS WebDAV
service due to improper handling of the 'If' header in a PROPFIND
request. An unauthenticated, remote attacker can exploit this, via a
specially crafted request, to cause a denial of service condition or
the execution of arbitrary code.

EXPLODINGCAN is one of multiple Equation Group vulnerabilities and
exploits disclosed on 2017/04/14 by a group known as the Shadow
Brokers.");
  # https://threatpost.com/publicly-attacked-microsoft-iis-zero-day-unlikely-to-be-patched/124641/
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c9ce665b");
  # https://www.theregister.co.uk/2017/03/31/microsoft_wont_patch_server_2003/
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?ca2c1085");
  script_set_attribute(attribute:"see_also", value:"https://github.com/edwardz246003/IIS_exploit/blob/master/exploit.py");
  # https://blog.0patch.com/2017/03/0patching-immortal-cve-2017-7269.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?91b46151");
  script_set_attribute(attribute:"solution", value:
"Windows Server 2003 and IIS 6.0 are no longer maintained or supported
by Microsoft. Upgrade to a currently supported version of Microsoft
Windows and IIS. Alternatively, disable either IIS or WebDAV.");
  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-2017-7269");

  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:"exploited_by_malware", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Microsoft IIS WebDav ScStoragePathFromUrl Overflow');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");
  script_set_attribute(attribute:"exploit_framework_canvas", value:"true");
  script_set_attribute(attribute:"canvas_package", value:"CANVAS");
  script_set_attribute(attribute:"in_the_news", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/03/26");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/04/20");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:microsoft:windows");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:iis");
  script_end_attributes();

  script_category(ACT_ATTACK);
  script_family(english:"Web Servers");

  script_copyright(english:"This script is Copyright (C) 2017-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("os_fingerprint.nasl", "webdav_enabled.nasl");
  script_require_keys("www/iis");
  script_require_ports("Services/www", 80);

  exit(0);
}

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

get_kb_item_or_exit("www/iis");
port = get_http_port(default:80);

app = "Microsoft IIS";
banner = get_http_banner(port:port);

if (banner !~ "Server: Microsoft-IIS") audit(AUDIT_NOT_DETECT, app, port);
else banner = strstr(banner, "Server:"); # slice banner

# ensure WebDAV is running
get_kb_item_or_exit("www/"+port+"/webdav");

# get IIS version
pat = "^Server: Microsoft-IIS\/([\d]+(?:\.[\d]+)+)";
version = pregmatch(string:banner, pattern:pat);
if (isnull(version)) audit(AUDIT_UNKNOWN_APP_VER, app);
else version = version[1];

if (version != '6.0') audit(AUDIT_INST_VER_NOT_VULN, app, version);

# ensure OS is Windows Server 2003, including R2
os = get_kb_item("Host/OS");
if (isnull(os) || "Server 2003" >!< os) os = get_kb_item("SMB/NativeLanManager");
if (isnull(os)) audit(AUDIT_OS_NOT, "known");
if ("Server 2003" >!< os) audit(AUDIT_OS_NOT, "Windows Server 2003");


pay='<http://localhost/' + crap(data:'A', length:0x82) + '>';
pay+=' (Not <locktoken:write1>) ';

hdrs = make_array("If", pay, "Host", "localhost", "Content-Length", 0);
res = http_send_recv3(
  method        : "PROPFIND",
  item          : "/",
  port          : port,
  add_headers   : hdrs, 
  exit_on_fail  : TRUE
);

if (res[0] =~ "^HTTP/[0-9]\.[0-9] 500") 
{
  if ("Internal Server Error(exception)" >< res[2])
  {
    report = 'Nessus was to able to detect the issue with the following request: \n\n' + http_last_sent_request(); 
    security_report_v4(port:port, extra:report, severity:SECURITY_HOLE);
  }
  else
  {
    audit(AUDIT_RESP_BAD, port, "a PROPFIND request. Unexpected HTTP 500 response body"); 
  }
}
else if (res[0] =~ "^HTTP/[0-9]\.[0-9] 207") 
{
  audit(AUDIT_INST_VER_NOT_VULN, app, version);
}
else
{
  audit(AUDIT_RESP_BAD, port, "a PROPFIND request. Unexpected response status: " + chomp(res[0])); 
}