SSL/TLS: TLS/SPDY Protocol Information Disclosure Vulnerability (CRIME)

# SPDX-FileCopyrightText: 2017 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.108094");
  script_version("2023-07-14T16:09:27+0000");
  script_cve_id("CVE-2012-4929", "CVE-2012-4930");
  script_tag(name:"cvss_base", value:"2.6");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:H/Au:N/C:P/I:N/A:N");
  script_tag(name:"last_modification", value:"2023-07-14 16:09:27 +0000 (Fri, 14 Jul 2023)");
  script_tag(name:"creation_date", value:"2017-03-09 16:00:00 +0100 (Thu, 09 Mar 2017)");
  script_name("SSL/TLS: TLS/SPDY Protocol Information Disclosure Vulnerability (CRIME)");
  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2017 Greenbone AG");
  script_family("SSL and TLS");
  script_dependencies("gb_tls_version_get.nasl", "gb_tls_npn_alpn_detect.nasl");
  script_require_ports("Services/www", 443);
  script_mandatory_keys("ssl_tls/port");

  script_xref(name:"URL", value:"http://www.securityfocus.com/bid/55704");
  script_xref(name:"URL", value:"http://www.securityfocus.com/bid/55707");
  script_xref(name:"URL", value:"http://permalink.gmane.org/gmane.comp.lib.qt.devel/6729");
  script_xref(name:"URL", value:"https://www.nccgroup.trust/us/about-us/newsroom-and-events/blog/2012/september/details-on-the-crime-attack/");

  script_tag(name:"summary", value:"The TLS/SPDY protocols are prone to an information-disclosure vulnerability.");

  script_tag(name:"solution", value:"Disable TLS compression in the configuration of this services. If SPDY below 4 is used upgrade
  the webserver to a version which supports the successor protocol SPDY/4 or HTTP/2.

  Please see the references for more resources supporting you with this task.");

  script_tag(name:"impact", value:"A man-in-the-middle attacker can exploit this issue to gain access to
  sensitive information that may aid in further attacks.");

  script_tag(name:"affected", value:"Services enabling TLS compression or supporting the SPDY protocol below SPDY/4 via HTTPS.");

  script_tag(name:"solution_type", value:"Mitigation");
  script_tag(name:"qod_type", value:"remote_app");

  exit(0);
}

include("mysql.inc");
include("http_func.inc");
include("port_service_func.inc");
include("misc_func.inc");
include("list_array_func.inc");
include("byte_func.inc");
include("ssl_funcs.inc");

comp_report  = 'The remote service might be vulnerable to the "CRIME" attack because it provides the following TLS compression methods:\n\nProtocol:Compression Method\n';
npn_report   = 'The remote service might be vulnerable to the "CRIME" attack because it advertises support for the following vulnerable Network Protocol(s) via the NPN extension:\n\nSSL/TLS Protocol:Network Protocol\n';
alpn_report  = 'The remote service might be vulnerable to the "CRIME" attack because it advertises support for the following vulnerable Network Protocol(s) via the ALPN extension:\n\nSSL/TLS Protocol:Network Protocol\n';

port = http_get_port( default:443, ignore_broken:TRUE, ignore_cgi_disabled:TRUE );

## Exit on non-ssl http port
if( get_port_transport( port ) < ENCAPS_SSLv23 ) exit( 0 );

if( ! versions = get_supported_tls_versions( port:port, min:SSL_v3 ) ) exit( 0 );

foreach version( versions ) {

  if( version == TLS_13 ) continue;

  # First check the TLS compression
  foreach compression_method( make_list( "DEFLATE", "LZS" ) ) {

    hello_done = FALSE;

    soc = open_ssl_socket( port:port );
    if( ! soc ) continue;

    hello = ssl_hello( port:port, version:version, compression_method:compression_method );
    if( ! hello ) {
      close( soc );
      continue;
    }

    send( socket:soc, data:hello );

    while( ! hello_done ) {

      data = ssl_recv( socket:soc );

      if( ! data ) {
        close( soc );
        break;
      }

      # Jump out if we're getting an ALERT (e.g. SSLv3_ALERT_DECODE_ERROR)
      record = search_ssl_record( data:data, search:make_array( "content_typ", SSLv3_ALERT ) );
      if( record ) {
        close( soc );
        break;
      }

      record = search_ssl_record( data:data, search: make_array( "handshake_typ", SSLv3_SERVER_HELLO ) );
      if( record ) {
        # The server will choose the asked compression or fail earlier with the DECODE_ERROR
        if( record['compression_method'] == ord( compression_methods[compression_method] ) ) {
          comp_vuln = TRUE;
          comp_report += version_string[version] + ":" + compression_method + '\n';
        }
      }

      record = search_ssl_record( data:data, search:make_array( "handshake_typ", SSLv3_SERVER_HELLO_DONE ) );
      if( record ) {
        hello_done = TRUE;
        break;
      }
    }
  }
}

foreach version( versions ) {

  if( ! SSL_VER = version_kb_string_mapping[version] ) continue;

  # This is the supported list gathered via NPN
  npn_prot_list = get_kb_list( "tls_npn_prot_supported/" + SSL_VER + "/" + port );
  foreach npn_prot( npn_prot_list ) {
    if( npn_prot =~ "spdy/[1-3]" ) {
      npn_vuln = TRUE;
      npn_report += version_string[version] + ":" + npn_alpn_name_mapping[npn_prot] + '\n';
    }
  }

  # This is the supported list gathered via ALPN
  alpn_prot_list = get_kb_list( "tls_alpn_prot_supported/" + SSL_VER + "/" + port );
  foreach alpn_prot( alpn_prot_list ) {
    if( alpn_prot =~ "spdy/[1-3]" ) {
      alpn_vuln = TRUE;
      alpn_report += version_string[version] + ":" + npn_alpn_name_mapping[alpn_prot] + '\n';
    }
  }
}

if( comp_vuln || npn_vuln || alpn_vuln ) {
  if( comp_vuln ) report += comp_report;
  if( npn_vuln )  report += '\n' + npn_report;
  if( alpn_vuln ) report += '\n' + alpn_report;
  security_message( port:port, data:report );
  exit( 0 );
}

exit( 99 );