Vulnerabilities > CVE-2015-6131 - Improper Input Validation vulnerability in Microsoft products

047910
CVSS 9.3 - CRITICAL
Attack vector
NETWORK
Attack complexity
MEDIUM
Privileges required
NONE
Confidentiality impact
COMPLETE
Integrity impact
COMPLETE
Availability impact
COMPLETE
network
microsoft
CWE-20
critical
nessus
exploit available

Summary

Windows Media Center in Microsoft Windows Vista SP2, Windows 7 SP1, Windows 8, and Windows 8.1 allows remote attackers to execute arbitrary code via a crafted .mcl file, aka "Media Center Library Parsing RCE Vulnerability."

Vulnerable Configurations

Part Description Count
OS
Microsoft
4

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Server Side Include (SSI) Injection
    An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
  • Cross Zone Scripting
    An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
  • Cross Site Scripting through Log Files
    An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
  • Command Line Execution through SQL Injection
    An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.

Exploit-Db

descriptionMicrosoft Windows Media Center Library Parsing RCE Vulnerability aka "self-executing" MCL File. CVE-2015-6131. Remote exploit for windows platform
fileexploits/windows/remote/38911.txt
idEDB-ID:38911
last seen2016-02-04
modified2015-12-09
platformwindows
port
published2015-12-09
reporterEduardo Braun Prado
sourcehttps://www.exploit-db.com/download/38911/
titleMicrosoft Windows Media Center Library Parsing RCE Vulnerability aka "self-executing" MCL File
typeremote

Msbulletin

bulletin_idMS15-134
bulletin_url
date2015-12-08T00:00:00
impactRemote Code Execution
knowledgebase_id3108669
knowledgebase_url
severityImportant
titleSecurity Update for Windows Media Center to Address Remote Code Execution

Nessus

NASL familyWindows : Microsoft Bulletins
NASL idSMB_NT_MS15-134.NASL
descriptionThe remote Windows host is missing a security update. It is, therefore, affected by multiple vulnerabilities in the Windows Media Center : - An information disclosure vulnerability exists due to improper handling of Media Center link (.mcl) files. A remote attacker can exploit this vulnerability, via a specially crafted .mcl link file, to disclose local file system information. (CVE-2015-6127) - A remote code execution vulnerability exists due to improper handling of Media Center link (.mcl) files that reference malicious code. A remote attacker can exploit this vulnerability, via a compromised web page or email that hosts a crafted .mcl file, to gain privileges and take control of an affected system. (CVE-2015-6131)
last seen2020-06-01
modified2020-06-02
plugin id87263
published2015-12-08
reporterThis script is Copyright (C) 2015-2018 Tenable Network Security, Inc.
sourcehttps://www.tenable.com/plugins/nessus/87263
titleMS15-134: Security Update for Windows Media Center to Address Remote Code Execution (3108669)
code
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(87263);
  script_version("1.17");
  script_cvs_date("Date: 2018/11/15 20:50:31");

  script_cve_id("CVE-2015-6127", "CVE-2015-6131");
  script_bugtraq_id(78512, 78516);
  script_xref(name:"MSFT", value:"MS15-134");
  script_xref(name:"MSKB", value:"3108669");

  script_name(english:"MS15-134: Security Update for Windows Media Center to Address Remote Code Execution (3108669)");
  script_summary(english:"Checks the version of ehshell.dll.");

  script_set_attribute(attribute:"synopsis", value:
"The remote Windows host is affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The remote Windows host is missing a security update. It is,
therefore, affected by multiple vulnerabilities in the Windows Media
Center :

  - An information disclosure vulnerability exists due to
    improper handling of Media Center link (.mcl) files.
    A remote attacker can exploit this vulnerability, via a
    specially crafted .mcl link file, to disclose local file
    system information. (CVE-2015-6127)

  - A remote code execution vulnerability exists due to
    improper handling of Media Center link (.mcl) files that
    reference malicious code. A remote attacker can exploit
    this vulnerability, via a compromised web page or email
    that hosts a crafted .mcl file, to gain privileges and
    take control of an affected system. (CVE-2015-6131)");
  script_set_attribute(attribute:"see_also", value:"https://docs.microsoft.com/en-us/security-updates/SecurityBulletins/2015/ms15-134");
  script_set_attribute(attribute:"solution", value:
"Microsoft has released a set of patches for Vista, 7, 8, and 8.1.");
  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:H/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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:"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:"vuln_publication_date", value:"2015/12/08");
  script_set_attribute(attribute:"patch_publication_date", value:"2015/12/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2015/12/08");

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

  script_category(ACT_GATHER_INFO);
  script_family(english:"Windows : Microsoft Bulletins");

  script_copyright(english:"This script is Copyright (C) 2015-2018 Tenable Network Security, Inc.");

  script_dependencies("smb_hotfixes.nasl", "ms_bulletin_checks_possible.nasl");
  script_require_keys("SMB/MS_Bulletin_Checks/Possible");
  script_require_ports(139, 445, "Host/patch_management_checks");

  exit(0);
}

include("audit.inc");
include("smb_func.inc");
include("smb_hotfixes.inc");
include("smb_hotfixes_fcheck.inc");
include("smb_reg_query.inc");
include("misc_func.inc");

get_kb_item_or_exit('SMB/MS_Bulletin_Checks/Possible');
bulletin = 'MS15-134';
kb = '3108669';

kbs = make_list(kb);
if (get_kb_item("Host/patch_management_checks")) hotfix_check_3rd_party(bulletin:bulletin, kbs:kbs, severity:SECURITY_HOLE);

get_kb_item_or_exit("SMB/Registry/Enumerated", exit_code:1);

if (hotfix_check_sp_range(vista:'2', win7:'1', win8:'0', win81:'0') <= 0) audit(AUDIT_OS_SP_NOT_VULN);
if (hotfix_check_server_core() == 1) audit(AUDIT_WIN_SERVER_CORE);

vuln = 0;

systemroot = hotfix_get_systemroot();
if (!systemroot) audit(AUDIT_PATH_NOT_DETERMINED, 'system root');

registry_init();
hklm = registry_hive_connect(hive:HKEY_LOCAL_MACHINE, exit_on_fail:TRUE);
win_media_center_installed = get_registry_value(handle:hklm, item:"SOFTWARE\Clients\Media\Windows Media Center\");
if(win_media_center_installed == "Windows Media Center")
  win_media_center_installed = TRUE;
else win_media_center_installed = FALSE;
RegCloseKey(handle:hklm);
close_registry();

if(!win_media_center_installed)
  audit(AUDIT_NOT_INST, "Windows Media Center");

port = kb_smb_transport();
login  = kb_smb_login();
pass   = kb_smb_password();
domain = kb_smb_domain();

if(! smb_session_init()) audit(AUDIT_FN_FAIL, 'smb_session_init');

winsxs = ereg_replace(pattern:'^[A-Za-z]:(.*)', replace:"\1\WinSxS", string:systemroot);
winsxs_share = hotfix_path2share(path:systemroot);

rc = NetUseAdd(login:login, password:pass, domain:domain, share:winsxs_share);
if (rc != 1)
{
  NetUseDel();
  audit(AUDIT_SHARE_FAIL, winsxs_share);
}

key = "SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\ApplicabilityEvaluationCache\Package_for_KB3108669~31bf3856ad364e35~amd64~~6.2.1.0";

files = list_dir(basedir:winsxs, level:0, dir_pat:"msil_ehshell_31bf3856ad364e35_", file_pat:"^ehshell\.dll$", max_recurse:1);

# Vista
# File Only Exists of Media Center TV Pack is installed (which comes installed by OEM)
vuln += hotfix_check_winsxs(os:'6.0',
                            sp:2,
                            files:files,
                            versions:make_list('6.0.6002.19537','6.0.6002.23847'),
                            max_versions:make_list('6.0.6002.20000','6.0.6002.99999'),
                            bulletin:bulletin,
                            kb:kb,
                            key:key);

# Windows 7
vuln += hotfix_check_winsxs(os:'6.1',
                            sp:1,
                            files:files,
                            versions:make_list('6.1.7600.17545','6.1.7601.19061', '6.1.7601.23265'),
                            max_versions:make_list('6.1.7600.20000', '6.1.7601.20000', '6.1.7601.99999'),
                            bulletin:bulletin,
                            kb:kb,
                            key:key);
# Windows 8
vuln += hotfix_check_winsxs(os:'6.2',
                            sp:0,
                            files:files,
                            versions:make_list('6.2.9200.17569', '6.2.9200.21688'),
                            max_versions:make_list('6.2.9200.20000', '6.2.9200.99999'),
                            bulletin:bulletin,
                            kb:kb,
                            key:key);

# Windows 8.1
# Only Vulnerable if Windows Media Center ($10 add-on) is installed
vuln += hotfix_check_winsxs(os:'6.3',
                            sp:0,
                            files:files,
                            versions:make_list('6.3.9600.18124'),
                            max_versions:make_list('6.3.9600.99999'),
                            bulletin:bulletin,
                            kb:kb,
                            key:key);

# cleanup
NetUseDel();

if (vuln)
{
  set_kb_item(name:'SMB/Missing/'+bulletin, value:TRUE);
  hotfix_security_hole();
  hotfix_check_fversion_end();
  exit(0);
}
else
{
  hotfix_check_fversion_end();
  audit(AUDIT_HOST_NOT, 'affected');
}