Vulnerabilities > CVE-2017-18122 - Improper Verification of Cryptographic Signature vulnerability in multiple products

047910
CVSS 6.8 - MEDIUM
Attack vector
NETWORK
Attack complexity
MEDIUM
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
PARTIAL
Availability impact
PARTIAL

Summary

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

Vulnerable Configurations

Part Description Count
Application
Simplesamlphp
73
OS
Debian
3

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Padding Oracle Crypto Attack
    An attacker is able to efficiently decrypt data without knowing the decryption key if a target system leaks data on whether or not a padding error happened while decrypting the ciphertext. A target system that leaks this type of information becomes the padding oracle and an attacker is able to make use of that oracle to efficiently decrypt data without knowing the decryption key by issuing on average 128*b calls to the padding oracle (where b is the number of bytes in the ciphertext block). In addition to performing decryption, an attacker is also able to produce valid ciphertexts (i.e., perform encryption) by using the padding oracle, all without knowing the encryption key. Any cryptosystem can be vulnerable to padding oracle attacks if the encrypted messages are not authenticated to ensure their validity prior to decryption, and then the information about padding error is leaked to the attacker. This attack technique may be used, for instance, to break CAPTCHA systems or decrypt/modify state information stored in client side objects (e.g., hidden fields or cookies). This attack technique is a side-channel attack on the cryptosystem that uses a data leak from an improperly implemented decryption routine to completely subvert the cryptosystem. The one bit of information that tells the attacker whether a padding error during decryption has occurred, in whatever form it comes, is sufficient for the attacker to break the cryptosystem. That bit of information can come in a form of an explicit error message about a padding error, a returned blank page, or even the server taking longer to respond (a timing attack). This attack can be launched cross domain where an attacker is able to use cross-domain information leaks to get the bits of information from the padding oracle from a target system / service with which the victim is communicating. To do so an attacker sends a request containing ciphertext to the target system. Due to the browser's same origin policy, the attacker is not able to see the response directly, but can use cross-domain information leak techniques to still get the information needed (i.e., information on whether or not a padding error has occurred). For instance, this can be done using "img" tag plus the onerror()/onload() events. The attacker's JavaScript can make web browsers to load an image on the target site, and know if the image is loaded or not. This is 1-bit information needed for the padding oracle attack to work: if the image is loaded, then it is valid padding, otherwise it is not.

Nessus

  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DSA-4127.NASL
    descriptionSeveral vulnerabilities have been discovered in SimpleSAMLphp, a framework for authentication, primarily via the SAML protocol. - CVE-2017-12867 Attackers with access to a secret token could extend its validity period by manipulating the prepended time offset. - CVE-2017-12869 When using the multiauth module, attackers can bypass authentication context restrictions and use any authentication source defined in the config. - CVE-2017-12873 Defensive measures have been taken to prevent the administrator from misconfiguring persistent NameIDs to avoid identifier clash. (Affects Debian 8 Jessie only.) - CVE-2017-12874 The InfoCard module could accept incorrectly signed XML messages in rare occasions. - CVE-2017-18121 The consentAdmin module was vulnerable to a Cross-Site Scripting attack, allowing an attacker to craft links that could execute arbitrary JavaScript code in the victim
    last seen2020-06-01
    modified2020-06-02
    plugin id107119
    published2018-03-05
    reporterThis script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/107119
    titleDebian DSA-4127-1 : simplesamlphp - security update
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were  
    # extracted from Debian Security Advisory DSA-4127. The text 
    # itself is copyright (C) Software in the Public Interest, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(107119);
      script_version("3.3");
      script_cvs_date("Date: 2018/11/13 12:30:46");
    
      script_cve_id("CVE-2017-12867", "CVE-2017-12869", "CVE-2017-12873", "CVE-2017-12874", "CVE-2017-18121", "CVE-2017-18122", "CVE-2018-6519", "CVE-2018-6521", "CVE-2018-7644");
      script_xref(name:"DSA", value:"4127");
    
      script_name(english:"Debian DSA-4127-1 : simplesamlphp - 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:
    "Several vulnerabilities have been discovered in SimpleSAMLphp, a
    framework for authentication, primarily via the SAML protocol.
    
      - CVE-2017-12867
        Attackers with access to a secret token could extend its
        validity period by manipulating the prepended time
        offset.
    
      - CVE-2017-12869
        When using the multiauth module, attackers can bypass
        authentication context restrictions and use any
        authentication source defined in the config.
    
      - CVE-2017-12873
        Defensive measures have been taken to prevent the
        administrator from misconfiguring persistent NameIDs to
        avoid identifier clash. (Affects Debian 8 Jessie only.)
    
      - CVE-2017-12874
        The InfoCard module could accept incorrectly signed XML
        messages in rare occasions.
    
      - CVE-2017-18121
        The consentAdmin module was vulnerable to a Cross-Site
        Scripting attack, allowing an attacker to craft links
        that could execute arbitrary JavaScript code in the
        victim's browser.
    
      - CVE-2017-18122
        The (deprecated) SAML 1.1 implementation would regard as
        valid any unsigned SAML response containing more than
        one signed assertion, provided that the signature of at
        least one of the assertions was valid, allowing an
        attacker that could obtain a valid signed assertion from
        an IdP to impersonate users from that IdP.
    
      - CVE-2018-6519
        Regular expression denial of service when parsing
        extraordinarily long timestamps.
    
      - CVE-2018-6521
        Change sqlauth module MySQL charset from utf8 to utf8mb
        to prevent theoretical query truncation that could allow
        remote attackers to bypass intended access restrictions
    
      - CVE-2018-7644
        Critical signature validation vulnerability."
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=889286"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security-tracker.debian.org/tracker/CVE-2017-12867"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security-tracker.debian.org/tracker/CVE-2017-12869"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security-tracker.debian.org/tracker/CVE-2017-12873"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security-tracker.debian.org/tracker/CVE-2017-12874"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security-tracker.debian.org/tracker/CVE-2017-18121"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security-tracker.debian.org/tracker/CVE-2017-18122"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security-tracker.debian.org/tracker/CVE-2018-6519"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security-tracker.debian.org/tracker/CVE-2018-6521"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security-tracker.debian.org/tracker/CVE-2018-7644"
      );
      # https://security-tracker.debian.org/tracker/source-package/simplesamlphp
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?b2a51c10"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://packages.debian.org/source/jessie/simplesamlphp"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://packages.debian.org/source/stretch/simplesamlphp"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://www.debian.org/security/2018/dsa-4127"
      );
      script_set_attribute(
        attribute:"solution", 
        value:
    "Upgrade the simplesamlphp packages.
    
    For the oldstable distribution (jessie), these problems have been
    fixed in version 1.13.1-2+deb8u1.
    
    For the stable distribution (stretch), these problems have been fixed
    in version 1.14.11-1+deb9u1."
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
      script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:simplesamlphp");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:8.0");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:9.0");
    
      script_set_attribute(attribute:"patch_publication_date", value:"2018/03/02");
      script_set_attribute(attribute:"plugin_publication_date", value:"2018/03/05");
      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:"8.0", prefix:"simplesamlphp", reference:"1.13.1-2+deb8u1")) flag++;
    if (deb_check(release:"9.0", prefix:"simplesamlphp", reference:"1.14.11-1+deb9u1")) flag++;
    
    if (flag)
    {
      if (report_verbosity > 0) security_hole(port:0, extra:deb_report_get());
      else security_hole(0);
      exit(0);
    }
    else audit(AUDIT_HOST_NOT, "affected");
    
  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DLA-1273.NASL
    descriptionsimplesamlphp, an authentication and federation application has been found vulnerable to Cross Site Scripting (XSS), signature validation byepass and using insecure connection charset. CVE-2017-18121 A Cross Site Scripting (XSS) issue has been found in the consentAdmin module of SimpleSAMLphp through 1.14.15, allowing an attacker to manually craft links that a victim can open, executing arbitrary JavaScript code. CVE-2017-18122 A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP. CVE-2018-6521 The sqlauth module in SimpleSAMLphp before 1.15.2 relies on the MySQL utf8 charset, which truncates queries upon encountering four-byte characters. There might be a scenario in which this allows remote attackers to bypass intended access restrictions. For Debian 7
    last seen2020-03-17
    modified2018-02-09
    plugin id106697
    published2018-02-09
    reporterThis script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/106697
    titleDebian DLA-1273-1 : simplesamlphp security update
    code
    #%NASL_MIN_LEVEL 80502
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were
    # extracted from Debian Security Advisory DLA-1273-1. The text
    # itself is copyright (C) Software in the Public Interest, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(106697);
      script_version("3.6");
      script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/12");
    
      script_cve_id("CVE-2017-18121", "CVE-2017-18122", "CVE-2018-6521");
    
      script_name(english:"Debian DLA-1273-1 : simplesamlphp 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 update."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "simplesamlphp, an authentication and federation application has been
    found vulnerable to Cross Site Scripting (XSS), signature validation
    byepass and using insecure connection charset.
    
    CVE-2017-18121
    
    A Cross Site Scripting (XSS) issue has been found in the consentAdmin
    module of SimpleSAMLphp through 1.14.15, allowing an attacker to
    manually craft links that a victim can open, executing arbitrary
    JavaScript code.
    
    CVE-2017-18122
    
    A signature-validation bypass issue was discovered in SimpleSAMLphp
    through 1.14.16. Service Provider using SAML 1.1 will regard as valid
    any unsigned SAML response containing more than one signed assertion,
    provided that the signature of at least one of the assertions is
    valid. Attributes contained in all the assertions received will be
    merged and the entityID of the first assertion received will be used,
    allowing an attacker to impersonate any user of any IdP given an
    assertion signed by the targeted IdP.
    
    CVE-2018-6521
    
    The sqlauth module in SimpleSAMLphp before 1.15.2 relies on the MySQL
    utf8 charset, which truncates queries upon encountering four-byte
    characters. There might be a scenario in which this allows remote
    attackers to bypass intended access restrictions.
    
    For Debian 7 'Wheezy', these problems have been fixed in version
    1.9.2-1+deb7u2.
    
    We recommend that you upgrade your simplesamlphp packages.
    
    NOTE: Tenable Network Security has extracted the preceding description
    block directly from the DLA 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://lists.debian.org/debian-lts-announce/2018/02/msg00008.html"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://packages.debian.org/source/wheezy/simplesamlphp"
      );
      script_set_attribute(
        attribute:"solution", 
        value:"Upgrade the affected simplesamlphp package."
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
      script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
      script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
      script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
      script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
      script_set_attribute(attribute:"exploit_available", value:"false");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:simplesamlphp");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:7.0");
    
      script_set_attribute(attribute:"patch_publication_date", value:"2018/02/08");
      script_set_attribute(attribute:"plugin_publication_date", value:"2018/02/09");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2018-2020 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:"7.0", prefix:"simplesamlphp", reference:"1.9.2-1+deb7u2")) flag++;
    
    if (flag)
    {
      if (report_verbosity > 0) security_hole(port:0, extra:deb_report_get());
      else security_hole(0);
      exit(0);
    }
    else audit(AUDIT_HOST_NOT, "affected");