Vulnerabilities > CVE-2017-1000391 - Improper Input Validation vulnerability in Jenkins

047910
CVSS 4.9 - MEDIUM
Attack vector
NETWORK
Attack complexity
MEDIUM
Privileges required
SINGLE
Confidentiality impact
NONE
Integrity impact
PARTIAL
Availability impact
PARTIAL
network
jenkins
CWE-20
nessus

Summary

Jenkins versions 2.88 and earlier and 2.73.2 and earlier stores metadata related to 'people', which encompasses actual user accounts, as well as users appearing in SCM, in directories corresponding to the user ID on disk. These directories used the user ID for their name without additional escaping, potentially resulting in problems like overwriting of unrelated configuration files.

Vulnerable Configurations

Part Description Count
Application
Jenkins
865

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.

Nessus

NASL familyCGI abuses
NASL idJENKINS_2_89.NASL
descriptionThe version of Jenkins running on the remote web server is prior to 2.89 or is a version of Jenkins LTS prior to 2.73.3. It is, therefore, affected by multiple vulnerabilities : - Jenkins contains a flaw that allows traversing outside of a restricted path. The issue is due to the program not properly sanitizing user input, specifically slashes and path traversal style attacks (e.g.
last seen2020-06-01
modified2020-06-02
plugin id104634
published2017-11-16
reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/104634
titleJenkins < 2.73.3 / 2.89 Multiple Vulnerabilities
code
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(104634);
  script_version("1.7");
  script_cvs_date("Date: 2019/11/12");

  script_cve_id("CVE-2017-1000391", "CVE-2017-1000392");
  script_bugtraq_id(101773);

  script_name(english:"Jenkins < 2.73.3 / 2.89 Multiple Vulnerabilities");
  script_summary(english:"Checks the Jenkins version.");

  script_set_attribute(attribute:"synopsis", value:
"A job scheduling and management system hosted on the remote web server
is affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The version of Jenkins running on the remote web server is prior to
2.89 or is a version of Jenkins LTS prior to 2.73.3.
It is, therefore, affected by multiple vulnerabilities :

  - Jenkins contains a flaw that allows traversing outside of a
  restricted path. The issue is due to the program not properly
  sanitizing user input, specifically slashes and path traversal
  style attacks (e.g. '../') supplied via usernames. With a
  specially crafted username, a remote attacker can overwrite
  arbitrary files on the system.

  - Jenkins contains a flaw that allows a stored cross-site
  scripting (XSS) attack. This flaw exists because the program
  does not validate autocomplete suggestions before returning it
  to users. This may allow a remote attacker to create a specially
  crafted request that will execute arbitrary script code in a
  user's browser session within the trust relationship between
  their browser and the server.

Note that Nessus has not tested for these issues but has instead
relied only on the application's self-reported version number.");
  script_set_attribute(attribute:"see_also", value:"https://jenkins.io/security/advisory/2017-11-08/");
  script_set_attribute(attribute:"solution", value:
"Upgrade Jenkins to version 2.89 or later, Jenkins LTS to version
2.73.3 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:S/C:N/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:ND");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:X");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-1000391");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/11/08");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/11/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/11/16");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:cloudbees:jenkins");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("jenkins_detect.nasl");
  script_require_keys("www/Jenkins");
  script_require_ports("Services/www", 8080);

  exit(0);
}

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

port = get_http_port(default:8080);
get_kb_item_or_exit("www/Jenkins/"+port+"/Installed");
url = build_url(qs:'/', port:port);

version = '';
fix = '';
if (get_kb_item("www/Jenkins/"+port+"/is_LTS") )
{
  appname = "Jenkins Open Source LTS";
  fix = '2.73.3';
}
else
{
  appname = "Jenkins Open Source";
  fix = '2.89';
}

version = get_kb_item("www/Jenkins/" + port + "/JenkinsVersion");
if (version == 'unknown')
{
  audit(AUDIT_UNKNOWN_WEB_APP_VER, appname, url);
}

if (ver_compare(ver:version, fix:fix, strict:FALSE) < 0)
{
  report =
    '\n  URL           : ' + url +
    '\n  Product       : ' + appname +
    '\n  Version       : ' + version +
    '\n  Fixed version : ' + fix +
    '\n';

  security_report_v4(port:port, severity:SECURITY_WARNING, extra:report, xss:TRUE);
}
else audit(AUDIT_WEB_APP_NOT_AFFECTED, appname, url, version);