Vulnerabilities > CVE-2017-7572 - Race Condition vulnerability in Backintime Project Backintime

047910
CVSS 9.3 - CRITICAL
Attack vector
NETWORK
Attack complexity
MEDIUM
Privileges required
NONE
Confidentiality impact
COMPLETE
Integrity impact
COMPLETE
Availability impact
COMPLETE
network
backintime-project
CWE-362
critical
nessus
NVD
Published: 2017-04-06
Updated: 2017-04-12

Summary

The _checkPolkitPrivilege function in serviceHelper.py in Back In Time (aka backintime) 1.1.18 and earlier uses a deprecated polkit authorization method (unix-process) that is subject to a race condition (time of check, time of use). With this authorization method, the owner of a process requesting a polkit operation is checked by polkitd via /proc/<pid>/status, by which time the requesting process may have been replaced by a different process with the same PID that has different privileges then the original requester.

Vulnerable Configurations

Part Description Count
Application
Backintime_Project
47

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Leveraging Race Conditions
    This attack targets a race condition occurring when multiple processes access and manipulate the same resource concurrently and the outcome of the execution depends on the particular order in which the access takes place. The attacker can leverage a race condition by "running the race", modifying the resource and modifying the normal execution flow. For instance a race condition can occur while accessing a file, the attacker can trick the system by replacing the original file with his version and cause the system to read the malicious file.
  • Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions
    This attack targets a race condition occurring between the time of check (state) for a resource and the time of use of a resource. The typical example is the file access. The attacker can leverage a file access race condition by "running the race", meaning that he would modify the resource between the first time the target program accesses the file and the time the target program uses the file. During that period of time, the attacker could do something such as replace the file and cause an escalation of privilege.

Nessus

  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2017-8DCE7A3940.NASL
    description - update to 1.1.20 - fixes CVE-2017-7572 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
    modified2017-04-24
    plugin id99611
    published2017-04-24
    reporterThis script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/99611
    titleFedora 25 : backintime (2017-8dce7a3940)
    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-2017-8dce7a3940.
#

include("compat.inc");

if (description)
{
  script_id(99611);
  script_version("3.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2017-7572");
  script_xref(name:"FEDORA", value:"2017-8dce7a3940");

  script_name(english:"Fedora 25 : backintime (2017-8dce7a3940)");
  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 1.1.20

  - fixes CVE-2017-7572

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-2017-8dce7a3940"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected backintime package."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C");
  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:backintime");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:25");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/04/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/04/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/04/24");
  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:"^25([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 25", "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:"FC25", reference:"backintime-1.1.20-1.fc25")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    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, "backintime");
}
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2017-525.NASL
    descriptionThis update for backintime to version 1.1.20 fixes several issues. These security issues were fixed : - CVE-2017-7572: The _checkPolkitPrivilege function in serviceHelper.py in backintime used a deprecated polkit authorization method (unix-process) that is subject to a race condition (time of check, time of use) (bsc#1032717). - Don
    last seen2020-06-05
    modified2017-05-01
    plugin id99751
    published2017-05-01
    reporterThis script is Copyright (C) 2017-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/99751
    titleopenSUSE Security Update : backintime (openSUSE-2017-525)
    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-2017-525.
#
# The text description of this plugin is (C) SUSE LLC.
#

include("compat.inc");

if (description)
{
  script_id(99751);
  script_version("3.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2017-7572");

  script_name(english:"openSUSE Security Update : backintime (openSUSE-2017-525)");
  script_summary(english:"Check for the openSUSE-2017-525 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 backintime to version 1.1.20 fixes several issues.

These security issues were fixed :

  - CVE-2017-7572: The _checkPolkitPrivilege function in
    serviceHelper.py in backintime used a deprecated polkit
    authorization method (unix-process) that is subject to a
    race condition (time of check, time of use)
    (bsc#1032717).

  - Don't store passwords given to polkit helper

  - boo#1007723: General security hardening measures 

These non-security issues were fixed :

  - Delete udev configuration files on uninstall

  - Merge doc subpackage into main package"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.opensuse.org/show_bug.cgi?id=1007723"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.opensuse.org/show_bug.cgi?id=1032717"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected backintime packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C");
  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:backintime");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:backintime-lang");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:backintime-qt4");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:42.1");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:42.2");

  script_set_attribute(attribute:"patch_publication_date", value:"2017/04/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/05/01");
  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");

  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\.1|SUSE42\.2)$") audit(AUDIT_OS_RELEASE_NOT, "openSUSE", "42.1 / 42.2", release);
if (!get_kb_item("Host/SuSE/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);



flag = 0;

if ( rpm_check(release:"SUSE42.1", reference:"backintime-1.1.20-3.1") ) flag++;
if ( rpm_check(release:"SUSE42.1", reference:"backintime-lang-1.1.20-3.1") ) flag++;
if ( rpm_check(release:"SUSE42.1", reference:"backintime-qt4-1.1.20-3.1") ) flag++;
if ( rpm_check(release:"SUSE42.2", reference:"backintime-1.1.20-3.3.1") ) flag++;
if ( rpm_check(release:"SUSE42.2", reference:"backintime-lang-1.1.20-3.3.1") ) flag++;
if ( rpm_check(release:"SUSE42.2", reference:"backintime-qt4-1.1.20-3.3.1") ) flag++;

if (flag)
{
  if (report_verbosity > 0) security_hole(port:0, extra:rpm_report_get());
  else security_hole(0);
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "backintime / backintime-lang / backintime-qt4");
}
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2017-36EB9502B0.NASL
    description - update to 1.1.20 - fixes CVE-2017-7572 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
    modified2017-07-17
    plugin id101610
    published2017-07-17
    reporterThis script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/101610
    titleFedora 26 : backintime (2017-36eb9502b0)
    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-2017-36eb9502b0.
#

include("compat.inc");

if (description)
{
  script_id(101610);
  script_version("3.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2017-7572");
  script_xref(name:"FEDORA", value:"2017-36eb9502b0");

  script_name(english:"Fedora 26 : backintime (2017-36eb9502b0)");
  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 1.1.20

  - fixes CVE-2017-7572

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-2017-36eb9502b0"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected backintime package."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C");
  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:backintime");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:26");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/04/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/04/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/07/17");
  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:"backintime-1.1.20-1.fc26")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    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, "backintime");
}
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2017-7C9A9B2B36.NASL
    description - update to 1.1.20 - fixes CVE-2017-7572 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
    modified2017-04-24
    plugin id99610
    published2017-04-24
    reporterThis script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/99610
    titleFedora 24 : backintime (2017-7c9a9b2b36)
    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-2017-7c9a9b2b36.
#

include("compat.inc");

if (description)
{
  script_id(99610);
  script_version("3.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2017-7572");
  script_xref(name:"FEDORA", value:"2017-7c9a9b2b36");

  script_name(english:"Fedora 24 : backintime (2017-7c9a9b2b36)");
  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 1.1.20

  - fixes CVE-2017-7572

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-2017-7c9a9b2b36"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected backintime package."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C");
  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:backintime");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:24");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/04/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/04/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/04/24");
  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:"^24([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 24", "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:"FC24", reference:"backintime-1.1.20-1.fc24")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    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, "backintime");
}

References