Vulnerabilities > CVE-2013-4434 - Numeric Errors vulnerability in Dropbear SSH Project Dropbear SSH

047910
CVSS 5.0 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
NONE
Availability impact
NONE
network
low complexity
dropbear-ssh-project
CWE-189
nessus

Summary

Dropbear SSH Server before 2013.59 generates error messages for a failed logon attempt with different time delays depending on whether the user account exists, which allows remote attackers to discover valid usernames.

Common Weakness Enumeration (CWE)

Nessus

  • NASL familyMandriva Local Security Checks
    NASL idMANDRIVA_MDVSA-2013-261.NASL
    descriptionUpdated dropbear package fixes security vulnerability : Possible memory exhaustion denial of service due to the size of decompressed payloads in dropbear before 2013.59 (CVE-2013-4421). Inconsistent delays in authorization failures could be used to disclose the existence of valid user accounts in dropbear before 2013.59 (CVE-2013-4434).
    last seen2020-06-01
    modified2020-06-02
    plugin id70680
    published2013-10-29
    reporterThis script is Copyright (C) 2013-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/70680
    titleMandriva Linux Security Advisory : dropbear (MDVSA-2013:261)
    code
    #%NASL_MIN_LEVEL 80502
    
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were  
    # extracted from Mandriva Linux Security Advisory MDVSA-2013:261. 
    # The text itself is copyright (C) Mandriva S.A.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(70680);
      script_version("1.6");
      script_cvs_date("Date: 2019/08/02 13:32:55");
    
      script_cve_id("CVE-2013-4421", "CVE-2013-4434");
      script_bugtraq_id(62958, 62993);
      script_xref(name:"MDVSA", value:"2013:261");
    
      script_name(english:"Mandriva Linux Security Advisory : dropbear (MDVSA-2013:261)");
      script_summary(english:"Checks rpm output for the updated package");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote Mandriva Linux host is missing a security update."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "Updated dropbear package fixes security vulnerability :
    
    Possible memory exhaustion denial of service due to the size of
    decompressed payloads in dropbear before 2013.59 (CVE-2013-4421).
    
    Inconsistent delays in authorization failures could be used to
    disclose the existence of valid user accounts in dropbear before
    2013.59 (CVE-2013-4434)."
      );
      script_set_attribute(
        attribute:"see_also",
        value:"http://advisories.mageia.org/MGASA-2013-0318.html"
      );
      script_set_attribute(
        attribute:"solution", 
        value:"Update the affected dropbear package."
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
      script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/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:mandriva:linux:dropbear");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:mandriva:business_server:1");
    
      script_set_attribute(attribute:"patch_publication_date", value:"2013/10/28");
      script_set_attribute(attribute:"plugin_publication_date", value:"2013/10/29");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2013-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
      script_family(english:"Mandriva Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/cpu", "Host/Mandrake/release", "Host/Mandrake/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);
    if (!get_kb_item("Host/Mandrake/release")) audit(AUDIT_OS_NOT, "Mandriva / Mandake Linux");
    if (!get_kb_item("Host/Mandrake/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    cpu = get_kb_item("Host/cpu");
    if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
    if (cpu !~ "^(amd64|i[3-6]86|x86_64)$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Mandriva / Mandrake Linux", cpu);
    
    
    flag = 0;
    if (rpm_check(release:"MDK-MBS1", cpu:"x86_64", reference:"dropbear-2013.59-1.mbs1")) flag++;
    
    
    if (flag)
    {
      if (report_verbosity > 0) security_warning(port:0, extra:rpm_report_get());
      else security_warning(0);
      exit(0);
    }
    else audit(AUDIT_HOST_NOT, "affected");
    
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2013-839.NASL
    descriptiondropbear was updated to version 2013.60 to fix following bugs : - Fix
    last seen2020-06-05
    modified2014-06-13
    plugin id75194
    published2014-06-13
    reporterThis script is Copyright (C) 2014-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/75194
    titleopenSUSE Security Update : dropbear (openSUSE-SU-2013:1696-1)
    code
    #%NASL_MIN_LEVEL 80502
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were
    # extracted from openSUSE Security Update openSUSE-2013-839.
    #
    # The text description of this plugin is (C) SUSE LLC.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(75194);
      script_version("1.3");
      script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");
    
      script_cve_id("CVE-2013-4421", "CVE-2013-4434");
    
      script_name(english:"openSUSE Security Update : dropbear (openSUSE-SU-2013:1696-1)");
      script_summary(english:"Check for the openSUSE-2013-839 patch");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote openSUSE host is missing a security update."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "dropbear was updated to version 2013.60 to fix following bugs :
    
      - Fix 'make install' so that it doesn't always install to
        /bin and /sbin
    
      - Fix 'make install MULTI=1', installing manpages failed
    
      - Fix 'make install' when scp is included since it has no
        manpage
    
      - Make --disable-bundled-libtom work
    
      - used as bug fix release for bnc#845306 - VUL-0:
        CVE-2013-4421 and CVE-2013-4434
    
      - provided links for download sources
    
      - employed gpg-offline - verify sources 
    
      - imported upstream version 2013.59
    
      - Fix crash from -J command Thanks to Lluís
        Batlle i Rossell and Arnaud Mouiche for patches
    
      - Avoid reading too much from /proc/net/rt_cache since
        that causes system slowness. 
    
      - Improve EOF handling for half-closed connections Thanks
        to Catalin Patulea
    
      - Send a banner message to report PAM error messages
        intended for the user Patch from Martin Donnelly
    
      - Limit the size of decompressed payloads, avoids memory
        exhaustion denial of service Thanks to Logan Lamb for
        reporting and investigating it
    
      - Avoid disclosing existence of valid users through
        inconsistent delays Thanks to Logan Lamb for reporting
    
      - Update config.guess and config.sub for newer
        architectures
    
      - Avoid segfault in server for locked accounts
    
      - 'make install' now installs manpages dropbearkey.8 has
        been renamed to dropbearkey.1 manpage added for
        dropbearconvert
    
      - Get rid of one second delay when running non-interactive
        commands"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://bugzilla.novell.com/show_bug.cgi?id=845306"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://lists.opensuse.org/opensuse-updates/2013-11/msg00046.html"
      );
      script_set_attribute(
        attribute:"solution", 
        value:"Update the affected dropbear packages."
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:dropbear");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:dropbear-debuginfo");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:dropbear-debugsource");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:13.1");
    
      script_set_attribute(attribute:"patch_publication_date", value:"2013/11/07");
      script_set_attribute(attribute:"plugin_publication_date", value:"2014/06/13");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2014-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
      script_family(english:"SuSE Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/SuSE/release", "Host/SuSE/rpm-list", "Host/cpu");
    
      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/SuSE/release");
    if (isnull(release) || release =~ "^(SLED|SLES)") audit(AUDIT_OS_NOT, "openSUSE");
    if (release !~ "^(SUSE13\.1)$") audit(AUDIT_OS_RELEASE_NOT, "openSUSE", "13.1", release);
    if (!get_kb_item("Host/SuSE/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    ourarch = get_kb_item("Host/cpu");
    if (!ourarch) audit(AUDIT_UNKNOWN_ARCH);
    if (ourarch !~ "^(i586|i686|x86_64)$") audit(AUDIT_ARCH_NOT, "i586 / i686 / x86_64", ourarch);
    
    flag = 0;
    
    if ( rpm_check(release:"SUSE13.1", reference:"dropbear-2013.60-2.4.1") ) flag++;
    if ( rpm_check(release:"SUSE13.1", reference:"dropbear-debuginfo-2013.60-2.4.1") ) flag++;
    if ( rpm_check(release:"SUSE13.1", reference:"dropbear-debugsource-2013.60-2.4.1") ) 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, "dropbear / dropbear-debuginfo / dropbear-debugsource");
    }
    
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2013-811.NASL
    descriptiondropbear was updated to version 2013.60 to fix following bugs : - Fix
    last seen2020-06-05
    modified2014-06-13
    plugin id75182
    published2014-06-13
    reporterThis script is Copyright (C) 2014-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/75182
    titleopenSUSE Security Update : dropbear (openSUSE-SU-2013:1616-1)
  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_8C9B48D1371511E3A62400262D8B701D.NASL
    descriptionThe Dropbear project reports : A weakness and a vulnerability have been reported in Dropbear SSH Server, which can be exploited by malicious people to disclose certain sensitive information and cause a DoS.
    last seen2020-06-01
    modified2020-06-02
    plugin id70484
    published2013-10-18
    reporterThis script is Copyright (C) 2013-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/70484
    titleFreeBSD : dropbear -- exposure of sensitive information, DoS (8c9b48d1-3715-11e3-a624-00262d8b701d)
  • NASL familyMisc.
    NASL idDROPBEAR_SSH_59.NASL
    descriptionAccording to its self-reported banner, the version of Dropbear SSH running on this port is earlier than 2013.59. As such, it is potentially affected by multiple vulnerabilities : - A denial of service vulnerability caused by the way the
    last seen2020-06-01
    modified2020-06-02
    plugin id70545
    published2013-10-22
    reporterThis script is Copyright (C) 2013-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/70545
    titleDropbear SSH Server < 2013.59 Multiple Vulnerabilities