Vulnerabilities > CVE-2019-3461 - Race Condition vulnerability in Debian Linux and Tmpreaper

047910
CVSS 7.0 - HIGH
Attack vector
LOCAL
Attack complexity
HIGH
Privileges required
LOW
Confidentiality impact
HIGH
Integrity impact
HIGH
Availability impact
HIGH
local
high complexity
debian
CWE-362
nessus

Summary

Debian tmpreaper version 1.6.13+nmu1 has a race condition when doing a (bind) mount via rename() which could result in local privilege escalation. Mounting via rename() could potentially lead to a file being placed elsewhereon the filesystem hierarchy (e.g. /etc/cron.d/) if the directory being cleaned up was on the same physical filesystem. Fixed versions include 1.6.13+nmu1+deb9u1 and 1.6.14.

Vulnerable Configurations

Part Description Count
Application
Debian
1
OS
Debian
2

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 familyDebian Local Security Checks
    NASL idDEBIAN_DLA-1640.NASL
    descriptionIt was discovered that tmpreaper, a program that cleans up files in directories based on their age, is vulnerable to a race condition. This vulnerability might be exploited by local attackers to perform privilege escalation. For Debian 8
    last seen2020-03-17
    modified2019-01-25
    plugin id121372
    published2019-01-25
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/121372
    titleDebian DLA-1640-1 : tmpreaper security update
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were
    # extracted from Debian Security Advisory DLA-1640-1. The text
    # itself is copyright (C) Software in the Public Interest, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(121372);
      script_version("1.3");
      script_set_attribute(attribute:"plugin_modification_date", value:"2020/02/20");
    
      script_cve_id("CVE-2019-3461");
    
      script_name(english:"Debian DLA-1640-1 : tmpreaper 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:
    "It was discovered that tmpreaper, a program that cleans up files in
    directories based on their age, is vulnerable to a race condition.
    This vulnerability might be exploited by local attackers to perform
    privilege escalation.
    
    For Debian 8 'Jessie', this problem has been fixed in version
    1.6.13+nmu1+deb8u1.
    
    We recommend that you upgrade your tmpreaper 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/2019/01/msg00017.html"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://packages.debian.org/source/jessie/tmpreaper"
      );
      script_set_attribute(
        attribute:"solution", 
        value:"Upgrade the affected tmpreaper package."
      );
      script_set_cvss_base_vector("CVSS2#AV:L/AC:M/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:L/AC:H/PR:L/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:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:tmpreaper");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:8.0");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2019/02/04");
      script_set_attribute(attribute:"patch_publication_date", value:"2019/01/24");
      script_set_attribute(attribute:"plugin_publication_date", value:"2019/01/25");
      script_set_attribute(attribute:"generated_plugin", value:"current");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2019-2020 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:"8.0", prefix:"tmpreaper", reference:"1.6.13+nmu1+deb8u1")) 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");
    
  • NASL familyUbuntu Local Security Checks
    NASL idUBUNTU_USN-4077-1.NASL
    descriptionIt was discovered that tmpreaper incorrectly handled certain mount operations. A local attacker could possibly use this issue to create arbitrary files, leading to privilege escalation. Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-01
    modified2020-06-02
    plugin id127793
    published2019-08-12
    reporterUbuntu Security Notice (C) 2019-2020 Canonical, Inc. / NASL script (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/127793
    titleUbuntu 16.04 LTS / 18.04 LTS : tmpreaper vulnerability (USN-4077-1)
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were
    # extracted from Ubuntu Security Notice USN-4077-1. The text 
    # itself is copyright (C) Canonical, Inc. See 
    # <http://www.ubuntu.com/usn/>. Ubuntu(R) is a registered 
    # trademark of Canonical, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(127793);
      script_version("1.3");
      script_cvs_date("Date: 2020/01/02");
    
      script_cve_id("CVE-2019-3461");
      script_xref(name:"USN", value:"4077-1");
    
      script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS : tmpreaper vulnerability (USN-4077-1)");
      script_summary(english:"Checks dpkg output for updated package.");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote Ubuntu host is missing a security-related patch."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "It was discovered that tmpreaper incorrectly handled certain mount
    operations. A local attacker could possibly use this issue to create
    arbitrary files, leading to privilege escalation.
    
    Note that Tenable Network Security has extracted the preceding
    description block directly from the Ubuntu 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://usn.ubuntu.com/4077-1/"
      );
      script_set_attribute(
        attribute:"solution", 
        value:"Update the affected tmpreaper package."
      );
      script_set_cvss_base_vector("CVSS2#AV:L/AC:M/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:L/AC:H/PR:L/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:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:tmpreaper");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2019/02/04");
      script_set_attribute(attribute:"patch_publication_date", value:"2019/07/29");
      script_set_attribute(attribute:"plugin_publication_date", value:"2019/08/12");
      script_set_attribute(attribute:"generated_plugin", value:"current");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"Ubuntu Security Notice (C) 2019-2020 Canonical, Inc. / NASL script (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
      script_family(english:"Ubuntu Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");
    
      exit(0);
    }
    
    
    include("audit.inc");
    include("ubuntu.inc");
    include("misc_func.inc");
    
    if ( ! get_kb_item("Host/local_checks_enabled") ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
    release = get_kb_item("Host/Ubuntu/release");
    if ( isnull(release) ) audit(AUDIT_OS_NOT, "Ubuntu");
    release = chomp(release);
    if (! preg(pattern:"^(16\.04|18\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 16.04 / 18.04", "Ubuntu " + release);
    if ( ! get_kb_item("Host/Debian/dpkg-l") ) 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, "Ubuntu", cpu);
    
    flag = 0;
    
    if (ubuntu_check(osver:"16.04", pkgname:"tmpreaper", pkgver:"1.6.13+nmu1+deb9u1build0.16.04.1")) flag++;
    if (ubuntu_check(osver:"18.04", pkgname:"tmpreaper", pkgver:"1.6.13+nmu1+deb9u1build0.18.04.1")) flag++;
    
    if (flag)
    {
      security_report_v4(
        port       : 0,
        severity   : SECURITY_WARNING,
        extra      : ubuntu_report_get()
      );
      exit(0);
    }
    else
    {
      tested = ubuntu_pkg_tests_get();
      if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
      else audit(AUDIT_PACKAGE_NOT_INSTALLED, "tmpreaper");
    }
    
  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DSA-4365.NASL
    descriptionStephen Roettger discovered a race condition in tmpreaper, a program that cleans up files in directories based on their age, which could result in local privilege escalation.
    last seen2020-03-17
    modified2019-01-14
    plugin id121134
    published2019-01-14
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/121134
    titleDebian DSA-4365-1 : tmpreaper - security update