Vulnerabilities > CVE-2018-8048 - Cross-site Scripting vulnerability in multiple products
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
LOW Integrity impact
LOW Availability impact
NONE Summary
In the Loofah gem through 2.2.0 for Ruby, non-whitelisted HTML attributes may occur in sanitized output by republishing a crafted HTML fragment.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
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 family FreeBSD Local Security Checks NASL id FREEBSD_PKG_81946ACE69614488A16422D58EBC8D66.NASL description OSS-Security list : There is a possible XSS vulnerability in rails-html-sanitizer. The gem allows non-whitelisted attributes to be present in sanitized output when input with specially crafted HTML fragments, and these attributes can lead to an XSS attack on target applications. This issue is similar to CVE-2018-8048 in Loofah. last seen 2020-06-01 modified 2020-06-02 plugin id 108624 published 2018-03-27 reporter This script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/108624 title FreeBSD : rails-html-sanitizer -- possible XSS vulnerability (81946ace-6961-4488-a164-22d58ebc8d66) code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from the FreeBSD VuXML database : # # Copyright 2003-2018 Jacques Vidrine and contributors # # Redistribution and use in source (VuXML) and 'compiled' forms (SGML, # HTML, PDF, PostScript, RTF and so forth) with or without modification, # are permitted provided that the following conditions are met: # 1. Redistributions of source code (VuXML) must retain the above # copyright notice, this list of conditions and the following # disclaimer as the first lines of this file unmodified. # 2. Redistributions in compiled form (transformed to other DTDs, # published online in any format, converted to PDF, PostScript, # RTF and other formats) must reproduce the above copyright # notice, this list of conditions and the following disclaimer # in the documentation and/or other materials provided with the # distribution. # # THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, # THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS # BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, # OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT # OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR # BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, # WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE # OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION, # EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. # include("compat.inc"); if (description) { script_id(108624); script_version("1.5"); script_cvs_date("Date: 2018/11/21 10:46:31"); script_cve_id("CVE-2018-3741"); script_name(english:"FreeBSD : rails-html-sanitizer -- possible XSS vulnerability (81946ace-6961-4488-a164-22d58ebc8d66)"); script_summary(english:"Checks for updated package in pkg_info output"); script_set_attribute( attribute:"synopsis", value:"The remote FreeBSD host is missing a security-related update." ); script_set_attribute( attribute:"description", value: "OSS-Security list : There is a possible XSS vulnerability in rails-html-sanitizer. The gem allows non-whitelisted attributes to be present in sanitized output when input with specially crafted HTML fragments, and these attributes can lead to an XSS attack on target applications. This issue is similar to CVE-2018-8048 in Loofah." ); # http://www.openwall.com/lists/oss-security/2018/03/22/4 script_set_attribute( attribute:"see_also", value:"https://www.openwall.com/lists/oss-security/2018/03/22/4" ); # https://vuxml.freebsd.org/freebsd/81946ace-6961-4488-a164-22d58ebc8d66.html script_set_attribute( attribute:"see_also", value:"http://www.nessus.org/u?cee2bf0f" ); script_set_attribute(attribute:"solution", value:"Update the affected 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:freebsd:freebsd:rubygem-rails-html-sanitizer"); script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd"); script_set_attribute(attribute:"vuln_publication_date", value:"2018/03/22"); script_set_attribute(attribute:"patch_publication_date", value:"2018/03/24"); script_set_attribute(attribute:"plugin_publication_date", value:"2018/03/27"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof."); script_family(english:"FreeBSD Local Security Checks"); script_dependencies("ssh_get_info.nasl"); script_require_keys("Host/local_checks_enabled", "Host/FreeBSD/release", "Host/FreeBSD/pkg_info"); exit(0); } include("audit.inc"); include("freebsd_package.inc"); if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED); if (!get_kb_item("Host/FreeBSD/release")) audit(AUDIT_OS_NOT, "FreeBSD"); if (!get_kb_item("Host/FreeBSD/pkg_info")) audit(AUDIT_PACKAGE_LIST_MISSING); flag = 0; if (pkg_test(save_report:TRUE, pkg:"rubygem-rails-html-sanitizer<1.0.4")) flag++; if (flag) { if (report_verbosity > 0) security_warning(port:0, extra:pkg_report_get()); else security_warning(0); exit(0); } else audit(AUDIT_HOST_NOT, "affected");NASL family Debian Local Security Checks NASL id DEBIAN_DSA-4171.NASL description The Shopify Application Security Team reported that ruby-loofah, a general library for manipulating and transforming HTML/XML documents and fragments, allows non-whitelisted attributes to be present in sanitized output when input with specially crafted HTML fragments. This might allow to mount a code injection attack into a browser consuming sanitized output. last seen 2020-06-01 modified 2020-06-02 plugin id 109046 published 2018-04-16 reporter This script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/109046 title Debian DSA-4171-1 : ruby-loofah - security update code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from Debian Security Advisory DSA-4171. The text # itself is copyright (C) Software in the Public Interest, Inc. # include("compat.inc"); if (description) { script_id(109046); script_version("1.5"); script_cvs_date("Date: 2018/11/13 12:30:46"); script_cve_id("CVE-2018-8048"); script_xref(name:"DSA", value:"4171"); script_name(english:"Debian DSA-4171-1 : ruby-loofah - security update"); script_summary(english:"Checks dpkg output for the updated package"); script_set_attribute( attribute:"synopsis", value:"The remote Debian host is missing a security-related update." ); script_set_attribute( attribute:"description", value: "The Shopify Application Security Team reported that ruby-loofah, a general library for manipulating and transforming HTML/XML documents and fragments, allows non-whitelisted attributes to be present in sanitized output when input with specially crafted HTML fragments. This might allow to mount a code injection attack into a browser consuming sanitized output." ); script_set_attribute( attribute:"see_also", value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=893596" ); script_set_attribute( attribute:"see_also", value:"https://security-tracker.debian.org/tracker/source-package/ruby-loofah" ); script_set_attribute( attribute:"see_also", value:"https://packages.debian.org/source/stretch/ruby-loofah" ); script_set_attribute( attribute:"see_also", value:"https://www.debian.org/security/2018/dsa-4171" ); script_set_attribute( attribute:"solution", value: "Upgrade the ruby-loofah packages. For the stable distribution (stretch), this problem has been fixed in version 2.0.3-2+deb9u1." ); 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:debian:debian_linux:ruby-loofah"); script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:9.0"); script_set_attribute(attribute:"patch_publication_date", value:"2018/04/13"); script_set_attribute(attribute:"plugin_publication_date", value:"2018/04/16"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof."); script_family(english:"Debian Local Security Checks"); script_dependencies("ssh_get_info.nasl"); script_require_keys("Host/local_checks_enabled", "Host/Debian/release", "Host/Debian/dpkg-l"); exit(0); } include("audit.inc"); include("debian_package.inc"); if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED); if (!get_kb_item("Host/Debian/release")) audit(AUDIT_OS_NOT, "Debian"); if (!get_kb_item("Host/Debian/dpkg-l")) audit(AUDIT_PACKAGE_LIST_MISSING); flag = 0; if (deb_check(release:"9.0", prefix:"ruby-loofah", reference:"2.0.3-2+deb9u1")) flag++; if (flag) { if (report_verbosity > 0) security_warning(port:0, extra:deb_report_get()); else security_warning(0); exit(0); } else audit(AUDIT_HOST_NOT, "affected");NASL family FreeBSD Local Security Checks NASL id FREEBSD_PKG_BA6D0C9BF5F64B9BA6DE3CCE93C83220.NASL description GitHub issue : This issue has been created for public disclosure of an XSS / code injection vulnerability that was responsibly reported by the Shopify Application Security Team. Loofah allows non-whitelisted attributes to be present in sanitized output when input with specially crafted HTML fragments. last seen 2020-06-01 modified 2020-06-02 plugin id 108508 published 2018-03-21 reporter This script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/108508 title FreeBSD : Loofah -- XSS vulnerability (ba6d0c9b-f5f6-4b9b-a6de-3cce93c83220) code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from the FreeBSD VuXML database : # # Copyright 2003-2018 Jacques Vidrine and contributors # # Redistribution and use in source (VuXML) and 'compiled' forms (SGML, # HTML, PDF, PostScript, RTF and so forth) with or without modification, # are permitted provided that the following conditions are met: # 1. Redistributions of source code (VuXML) must retain the above # copyright notice, this list of conditions and the following # disclaimer as the first lines of this file unmodified. # 2. Redistributions in compiled form (transformed to other DTDs, # published online in any format, converted to PDF, PostScript, # RTF and other formats) must reproduce the above copyright # notice, this list of conditions and the following disclaimer # in the documentation and/or other materials provided with the # distribution. # # THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, # THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS # BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, # OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT # OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR # BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, # WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE # OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION, # EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. # include("compat.inc"); if (description) { script_id(108508); script_version("1.4"); script_cvs_date("Date: 2018/11/10 11:49:47"); script_cve_id("CVE-2018-8048"); script_name(english:"FreeBSD : Loofah -- XSS vulnerability (ba6d0c9b-f5f6-4b9b-a6de-3cce93c83220)"); script_summary(english:"Checks for updated package in pkg_info output"); script_set_attribute( attribute:"synopsis", value:"The remote FreeBSD host is missing a security-related update." ); script_set_attribute( attribute:"description", value: "GitHub issue : This issue has been created for public disclosure of an XSS / code injection vulnerability that was responsibly reported by the Shopify Application Security Team. 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