Vulnerabilities > CVE-2015-7579 - Cross-site Scripting vulnerability in Rubyonrails Html Sanitizer 1.0.0/1.0.1/1.0.2

047910
CVSS 6.1 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
LOW
Integrity impact
LOW
Availability impact
NONE
network
low complexity
rubyonrails
CWE-79
nessus

Summary

Cross-site scripting (XSS) vulnerability in the rails-html-sanitizer gem 1.0.2 for Ruby on Rails 4.2.x and 5.x allows remote attackers to inject arbitrary web script or HTML via an HTML entity that is mishandled by the Rails::Html::FullSanitizer class.

Common Attack Pattern Enumeration and Classification (CAPEC)

  • 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.
  • Embedding Scripts in Non-Script Elements
    This attack is a form of Cross-Site Scripting (XSS) where malicious scripts are embedded in elements that are not expected to host scripts such as image tags (<img>), comments in XML documents (< !-CDATA->), etc. These tags may not be subject to the same input validation, output validation, and other content filtering and checking routines, so this can create an opportunity for an attacker to tunnel through the application's elements and launch a XSS attack through other elements. As with all remote attacks, it is important to differentiate the ability to launch an attack (such as probing an internal network for unpatched servers) and the ability of the remote attacker to collect and interpret the output of said attack.
  • Embedding Scripts within Scripts
    An attack of this type exploits a programs' vulnerabilities that are brought on by allowing remote hosts to execute scripts. The attacker leverages this capability to execute scripts to execute his/her own script by embedding it within other scripts that the target software is likely to execute. The attacker must have the ability to inject script into script that is likely to be executed. If this is done, then the attacker can potentially launch a variety of probes and attacks against the web server's local environment, in many cases the so-called DMZ, back end resources the web server can communicate with, and other hosts. With the proliferation of intermediaries, such as Web App Firewalls, network devices, and even printers having JVMs and Web servers, there are many locales where an attacker can inject malicious scripts. Since this attack pattern defines scripts within scripts, there are likely privileges to execute said attack on the host. Of course, these attacks are not solely limited to the server side, client side scripts like Ajax and client side JavaScript can contain malicious scripts as well. In general all that is required is for there to be sufficient privileges to execute a script, but not protected against writing.
  • Cross-Site Scripting in Error Pages
    An attacker distributes a link (or possibly some other query structure) with a request to a third party web server that is malformed and also contains a block of exploit code in order to have the exploit become live code in the resulting error page. When the third party web server receives the crafted request and notes the error it then creates an error message that echoes the malformed message, including the exploit. Doing this converts the exploit portion of the message into to valid language elements that are executed by the viewing browser. When a victim executes the query provided by the attacker the infected error message error message is returned including the exploit code which then runs in the victim's browser. XSS can result in execution of code as well as data leakage (e.g. session cookies can be sent to the attacker). This type of attack is especially dangerous since the exploit appears to come from the third party web server, who the victim may trust and hence be more vulnerable to deception.
  • Cross-Site Scripting Using Alternate Syntax
    The attacker uses alternate forms of keywords or commands that result in the same action as the primary form but which may not be caught by filters. For example, many keywords are processed in a case insensitive manner. If the site's web filtering algorithm does not convert all tags into a consistent case before the comparison with forbidden keywords it is possible to bypass filters (e.g., incomplete black lists) by using an alternate case structure. For example, the "script" tag using the alternate forms of "Script" or "ScRiPt" may bypass filters where "script" is the only form tested. Other variants using different syntax representations are also possible as well as using pollution meta-characters or entities that are eventually ignored by the rendering engine. The attack can result in the execution of otherwise prohibited functionality.

Nessus

  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2016-3A2606F993.NASL
    descriptionSecurity fix for CVE-2015-7578 CVE-2015-7579 CVE-2015-7580 Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-05
    modified2016-03-04
    plugin id89515
    published2016-03-04
    reporterThis script is Copyright (C) 2016-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/89515
    titleFedora 22 : rubygem-rails-html-sanitizer-1.0.1-2.fc22 (2016-3a2606f993)
    code
    #%NASL_MIN_LEVEL 80502
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were  
    # extracted from Fedora Security Advisory 2016-3a2606f993.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(89515);
      script_version("1.3");
      script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");
    
      script_cve_id("CVE-2015-7578", "CVE-2015-7579");
      script_xref(name:"FEDORA", value:"2016-3a2606f993");
    
      script_name(english:"Fedora 22 : rubygem-rails-html-sanitizer-1.0.1-2.fc22 (2016-3a2606f993)");
      script_summary(english:"Checks rpm output for the updated package.");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote Fedora host is missing a security update."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "Security fix for CVE-2015-7578 CVE-2015-7579 CVE-2015-7580
    
    Note that Tenable Network Security has extracted the preceding
    description block directly from the Fedora security advisory. Tenable
    has attempted to automatically clean and format it as much as possible
    without introducing additional issues."
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://bugzilla.redhat.com/show_bug.cgi?id=1301920"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://bugzilla.redhat.com/show_bug.cgi?id=1302014"
      );
      # https://lists.fedoraproject.org/pipermail/package-announce/2016-February/178046.html
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?96440aa9"
      );
      script_set_attribute(
        attribute:"solution", 
        value:"Update the affected rubygem-rails-html-sanitizer package."
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N");
      script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:rubygem-rails-html-sanitizer");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:22");
    
      script_set_attribute(attribute:"patch_publication_date", value:"2016/02/28");
      script_set_attribute(attribute:"plugin_publication_date", value:"2016/03/04");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2016-2020 Tenable Network Security, Inc.");
      script_family(english:"Fedora Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list");
    
      exit(0);
    }
    
    
    include("audit.inc");
    include("global_settings.inc");
    include("rpm.inc");
    
    if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
    release = get_kb_item("Host/RedHat/release");
    if (isnull(release) || "Fedora" >!< release) audit(AUDIT_OS_NOT, "Fedora");
    os_ver = eregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
    if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
    os_ver = os_ver[1];
    if (! ereg(pattern:"^22([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 22.x", "Fedora " + os_ver);
    
    if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    cpu = get_kb_item("Host/cpu");
    if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
    if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu);
    
    flag = 0;
    if (rpm_check(release:"FC22", reference:"rubygem-rails-html-sanitizer-1.0.1-2.fc22")) flag++;
    
    
    if (flag)
    {
      if (report_verbosity > 0) security_warning(port:0, extra:rpm_report_get());
      else security_warning(0);
      exit(0);
    }
    else
    {
      tested = pkg_tests_get();
      if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
      else audit(AUDIT_PACKAGE_NOT_INSTALLED, "rubygem-rails-html-sanitizer");
    }
    
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2016-148.NASL
    descriptionThis update for rubygem-rails-html-sanitizer fixes the following issues : - CVE-2015-7579: XSS vulnerability in rails-html-sanitizer (bsc#963327) - CVE-2015-7578: XSS vulnerability via attributes (bsc#963326) - CVE-2015-7580: XSS via whitelist sanitizer (bsc#963328)
    last seen2020-06-05
    modified2016-02-08
    plugin id88606
    published2016-02-08
    reporterThis script is Copyright (C) 2016-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/88606
    titleopenSUSE Security Update : rubygem-rails-html-sanitizer (openSUSE-2016-148)
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2016-59CE8B61DD.NASL
    descriptionSecurity fix for CVE-2015-7578 CVE-2015-7579 CVE-2015-7580 Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-05
    modified2016-03-04
    plugin id89549
    published2016-03-04
    reporterThis script is Copyright (C) 2016-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/89549
    titleFedora 23 : rubygem-rails-html-sanitizer-1.0.3-1.fc23 (2016-59ce8b61dd)

Seebug

bulletinFamilyexploit
descriptionXSS vulnerability in rails-html-sanitizer There is a XSS vulnerability in `Rails::Html::FullSanitizer` used by Action View's `strip_tags`. This vulnerability has been assigned the CVE identifier CVE-2015-7579. Versions Affected: 1.0.2 Not affected: 1.0.0, 1.0.1 Fixed Versions: 1.0.3 ### Impact Due to the way that `Rails::Html::FullSanitizer` is implemented, if an attacker passes an already escaped HTML entity to the input of Action View's `strip_tags` these entities will be unescaped what may cause a XSS attack if used in combination with `raw` or `html_safe`. For example: ``` strip_tags("&lt;script&gt;alert('XSS')&lt;/script&gt;") ``` Would generate: ``` <script>alert('XSS')</script> ``` After the fix it will generate: ``` &lt;script&gt;alert('XSS')&lt;/script&gt; ``` All users running an affected release should either upgrade or use one of the workarounds immediately. ### Releases The FIXED releases are available at the normal locations. ### Workarounds If you can't upgrade, please use the following monkey patch in an initializer that is loaded before your application: ``` $ cat config/initializers/strip_tags_fix.rb class ActionView::Base def strip_tags(html) self.class.full_sanitizer.sanitize(html) end end ``` ### 参考 * https://groups.google.com/forum/#!topic/rubyonrails-security/OU9ugTZcbjc
idSSV:90641
last seen2017-11-19
modified2016-01-27
published2016-01-27
reporterRoot
titleRuby on Rails rails-html-sanitizer XSS 漏洞