Vulnerabilities > CVE-2017-8821 - Improper Restriction of Operations within the Bounds of a Memory Buffer 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-119
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, an attacker can cause a denial of service (application hang) via crafted PEM input that signifies a public key requiring a password, which triggers an attempt by the OpenSSL library to ask the user for the password, aka TROVE-2017-011.

Vulnerable Configurations

Part Description Count
Application
Tor_Project
1
OS
Debian
2

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Overflow Buffers
    Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an attacker. As a consequence, an attacker is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the attackers' choice.
  • Client-side Injection-induced Buffer Overflow
    This type of attack exploits a buffer overflow vulnerability in targeted client software through injection of malicious content from a custom-built hostile service.
  • Filter Failure through Buffer Overflow
    In this attack, the idea is to cause an active filter to fail by causing an oversized transaction. An attacker may try to feed overly long input strings to the program in an attempt to overwhelm the filter (by causing a buffer overflow) and hoping that the filter does not fail securely (i.e. the user input is let into the system unfiltered).
  • MIME Conversion
    An attacker exploits a weakness in the MIME conversion routine to cause a buffer overflow and gain control over the mail server machine. The MIME system is designed to allow various different information formats to be interpreted and sent via e-mail. Attack points exist when data are converted to MIME compatible format and back.

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