Vulnerabilities > CVE-2017-8820 - NULL Pointer Dereference vulnerability in multiple products

047910
CVSS 7.5 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
HIGH
network
low complexity
tor-project
debian
CWE-476
nessus
NVD
Published: 2017-12-03
Updated: 2017-12-21

Summary

In Tor before 0.2.5.16, 0.2.6 through 0.2.8 before 0.2.8.17, 0.2.9 before 0.2.9.14, 0.3.0 before 0.3.0.13, and 0.3.1 before 0.3.1.9, remote attackers can cause a denial of service (NULL pointer dereference and application crash) against directory authorities via a malformed descriptor, aka TROVE-2017-010.

Vulnerable Configurations

Part Description Count
Application
Tor_Project
1
OS
Debian
2

Common Weakness Enumeration (CWE)

Nessus

  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2017-BC2EDC421D.NASL
    descriptionupdate to upstream release 0.3.1.9. Fixes various CVEs : - CVE-2017-8819: Replay-cache ineffective for v2 onion services - CVE-2017-8820: Remote DoS attack against directory authorities - CVE-2017-8821: An attacker can make Tor ask for a password - CVE-2017-8822: Relays can pick themselves in a circuit path - CVE-2017-8823: Use-after-free in onion service v2 Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-05
    modified2018-01-15
    plugin id105965
    published2018-01-15
    reporterThis script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/105965
    titleFedora 27 : tor (2017-bc2edc421d)
    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 FEDORA-2017-bc2edc421d.
#

include("compat.inc");

if (description)
{
  script_id(105965);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2017-8819", "CVE-2017-8820", "CVE-2017-8821", "CVE-2017-8822", "CVE-2017-8823");
  script_xref(name:"FEDORA", value:"2017-bc2edc421d");

  script_name(english:"Fedora 27 : tor (2017-bc2edc421d)");
  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:
"update to upstream release 0.3.1.9. Fixes various CVEs :

  - CVE-2017-8819: Replay-cache ineffective for v2 onion
    services

  - CVE-2017-8820: Remote DoS attack against directory
    authorities

  - CVE-2017-8821: An attacker can make Tor ask for a
    password

  - CVE-2017-8822: Relays can pick themselves in a circuit
    path

  - CVE-2017-8823: Use-after-free in onion service v2

Note that Tenable Network Security has extracted the preceding
description block directly from the Fedora update system website.
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://bodhi.fedoraproject.org/updates/FEDORA-2017-bc2edc421d"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected tor package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/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:fedoraproject:fedora:tor");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:27");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/12/03");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/12/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/01/15");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  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:"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 = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
os_ver = os_ver[1];
if (! preg(pattern:"^27([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 27", "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:"FC27", reference:"tor-0.3.1.9-1.fc27")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "tor");
}
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2017-1336.NASL
    descriptionThis update for tor fixes vulnerabilities that allowed some traffic confirmation, DoS and other attacks (bsc#1070849) : - CVE-2017-8819: Replay-cache ineffective for v2 onion services - CVE-2017-8820: Remote DoS attack against directory authorities - CVE-2017-8821: An attacker can make Tor ask for a password - CVE-2017-8822: Relays can pick themselves in a circuit path - CVE-2017-8823: Use-after-free in onion service v2
    last seen2020-06-05
    modified2017-12-14
    plugin id105227
    published2017-12-14
    reporterThis script is Copyright (C) 2017-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/105227
    titleopenSUSE Security Update : tor (openSUSE-2017-1336)
    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-2017-1336.
#
# The text description of this plugin is (C) SUSE LLC.
#

include("compat.inc");

if (description)
{
  script_id(105227);
  script_version("3.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2017-8819", "CVE-2017-8820", "CVE-2017-8821", "CVE-2017-8822", "CVE-2017-8823");

  script_name(english:"openSUSE Security Update : tor (openSUSE-2017-1336)");
  script_summary(english:"Check for the openSUSE-2017-1336 patch");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote openSUSE host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"This update for tor fixes vulnerabilities that allowed some traffic
confirmation, DoS and other attacks (bsc#1070849) :

  - CVE-2017-8819: Replay-cache ineffective for v2 onion
    services

  - CVE-2017-8820: Remote DoS attack against directory
    authorities

  - CVE-2017-8821: An attacker can make Tor ask for a
    password

  - CVE-2017-8822: Relays can pick themselves in a circuit
    path

  - CVE-2017-8823: Use-after-free in onion service v2"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.opensuse.org/show_bug.cgi?id=1070849"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected tor packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/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:novell:opensuse:tor");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:tor-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:tor-debugsource");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:42.2");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:42.3");

  script_set_attribute(attribute:"patch_publication_date", value:"2017/12/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/14");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2020 Tenable Network Security, Inc.");
  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 !~ "^(SUSE42\.2|SUSE42\.3)$") audit(AUDIT_OS_RELEASE_NOT, "openSUSE", "42.2 / 42.3", 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:"SUSE42.2", reference:"tor-0.2.9.14-8.12.1") ) flag++;
if ( rpm_check(release:"SUSE42.2", reference:"tor-debuginfo-0.2.9.14-8.12.1") ) flag++;
if ( rpm_check(release:"SUSE42.2", reference:"tor-debugsource-0.2.9.14-8.12.1") ) flag++;
if ( rpm_check(release:"SUSE42.3", reference:"tor-0.3.0.13-9.1") ) flag++;
if ( rpm_check(release:"SUSE42.3", reference:"tor-debuginfo-0.3.0.13-9.1") ) flag++;
if ( rpm_check(release:"SUSE42.3", reference:"tor-debugsource-0.3.0.13-9.1") ) 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, "tor / tor-debuginfo / tor-debugsource");
}
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2017-BCE9E03721.NASL
    descriptionupdate to upstream release 0.3.1.9. Fixes : - CVE-2017-8819: Replay-cache ineffective for v2 onion services - CVE-2017-8820: Remote DoS attack against directory authorities - CVE-2017-8821: An attacker can make Tor ask for a password - CVE-2017-8822: Relays can pick themselves in a circuit path - CVE-2017-8823: Use-after-free in onion service v2 Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-05
    modified2017-12-18
    plugin id105334
    published2017-12-18
    reporterThis script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/105334
    titleFedora 26 : tor (2017-bce9e03721)
    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 FEDORA-2017-bce9e03721.
#

include("compat.inc");

if (description)
{
  script_id(105334);
  script_version("3.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2017-8819", "CVE-2017-8820", "CVE-2017-8821", "CVE-2017-8822", "CVE-2017-8823");
  script_xref(name:"FEDORA", value:"2017-bce9e03721");

  script_name(english:"Fedora 26 : tor (2017-bce9e03721)");
  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:
"update to upstream release 0.3.1.9. Fixes :

  - CVE-2017-8819: Replay-cache ineffective for v2 onion
    services

  - CVE-2017-8820: Remote DoS attack against directory
    authorities

  - CVE-2017-8821: An attacker can make Tor ask for a
    password

  - CVE-2017-8822: Relays can pick themselves in a circuit
    path

  - CVE-2017-8823: Use-after-free in onion service v2

Note that Tenable Network Security has extracted the preceding
description block directly from the Fedora update system website.
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://bodhi.fedoraproject.org/updates/FEDORA-2017-bce9e03721"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected tor package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/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:fedoraproject:fedora:tor");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:26");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/12/03");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/12/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/18");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  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 = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
os_ver = os_ver[1];
if (! preg(pattern:"^26([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 26", "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:"FC26", reference:"tor-0.3.1.9-1.fc26")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "tor");
}
  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DSA-4054.NASL
    descriptionMultiple vulnerabilities have been found in Tor, a connection-based low-latency anonymous communication system.
    last seen2020-06-01
    modified2020-06-02
    plugin id104975
    published2017-12-04
    reporterThis script is Copyright (C) 2017-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/104975
    titleDebian DSA-4054-1 : tor - security update
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Debian Security Advisory DSA-4054. The text 
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(104975);
  script_version("3.5");
  script_cvs_date("Date: 2018/11/13 12:30:46");

  script_cve_id("CVE-2017-8819", "CVE-2017-8820", "CVE-2017-8821", "CVE-2017-8822", "CVE-2017-8823");
  script_xref(name:"DSA", value:"4054");

  script_name(english:"Debian DSA-4054-1 : tor - 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:
"Multiple vulnerabilities have been found in Tor, a connection-based
low-latency anonymous communication system."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/source-package/tor"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/jessie/tor"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/stretch/tor"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.debian.org/security/2017/dsa-4054"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Upgrade the tor packages.

For the oldstable distribution (jessie), these problems have been
fixed in version 0.2.5.16-1.

For the stable distribution (stretch), these problems have been fixed
in version 0.2.9.14-1."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/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:tor");
  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:"2017/12/03");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/04");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2018 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:"tor", reference:"0.2.5.16-1")) flag++;
if (deb_check(release:"8.0", prefix:"tor-dbg", reference:"0.2.5.16-1")) flag++;
if (deb_check(release:"8.0", prefix:"tor-geoipdb", reference:"0.2.5.16-1")) flag++;
if (deb_check(release:"9.0", prefix:"tor", reference:"0.2.9.14-1")) flag++;
if (deb_check(release:"9.0", prefix:"tor-dbg", reference:"0.2.9.14-1")) flag++;
if (deb_check(release:"9.0", prefix:"tor-geoipdb", reference:"0.2.9.14-1")) 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");

References