Vulnerabilities > CVE-2017-9502 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Haxx Curl
Summary
In curl before 7.54.1 on Windows and DOS, libcurl's default protocol function, which is the logic that allows an application to set which protocol libcurl should attempt to use when given a URL without a scheme part, had a flaw that could lead to it overwriting a heap based memory buffer with seven bytes. If the default protocol is specified to be FILE or a file: URL lacks two slashes, the given "URL" starts with a drive letter, and libcurl is built for Windows or DOS, then libcurl would copy the path 7 bytes off, so that the end of the given path would write beyond the malloc buffer (7 bytes being the length in bytes of the ascii string "file://").
Vulnerable Configurations
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 family FreeBSD Local Security Checks NASL id FREEBSD_PKG_9314058E520411E7B712B1A44A034D72.NASL description cURL security advisory : When libcurl is given either 1. a file: URL that doesn last seen 2020-06-01 modified 2020-06-02 plugin id 100828 published 2017-06-16 reporter This script is Copyright (C) 2017-2018 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/100828 title FreeBSD : cURL -- URL file scheme drive letter buffer overflow (9314058e-5204-11e7-b712-b1a44a034d72) code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from the FreeBSD VuXML database : # # Copyright 2003-2018 Jacques Vidrine and contributors # # Redistribution and use in source (VuXML) and 'compiled' forms (SGML, # HTML, PDF, PostScript, RTF and so forth) with or without modification, # are permitted provided that the following conditions are met: # 1. Redistributions of source code (VuXML) must retain the above # copyright notice, this list of conditions and the following # disclaimer as the first lines of this file unmodified. # 2. Redistributions in compiled form (transformed to other DTDs, # published online in any format, converted to PDF, PostScript, # RTF and other formats) must reproduce the above copyright # notice, this list of conditions and the following disclaimer # in the documentation and/or other materials provided with the # distribution. # # THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, # THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS # BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, # OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT # OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR # BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, # WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE # OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION, # EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. # include("compat.inc"); if (description) { script_id(100828); script_version("3.5"); script_cvs_date("Date: 2018/12/19 13:21:18"); script_cve_id("CVE-2017-9502"); script_name(english:"FreeBSD : cURL -- URL file scheme drive letter buffer overflow (9314058e-5204-11e7-b712-b1a44a034d72)"); script_summary(english:"Checks for updated package in pkg_info output"); script_set_attribute( attribute:"synopsis", value:"The remote FreeBSD host is missing a security-related update." ); script_set_attribute( attribute:"description", value: "cURL security advisory : When libcurl is given either 1. a file: URL that doesn't use two slashes following the colon, or 2. is told that file is the default scheme to use for URLs without scheme ... and the given path starts with a drive letter and libcurl is built for Windows or DOS, then libcurl would copy the path with a wrong offset, so that the end of the given path would write beyond the malloc buffer. Up to seven bytes too much. We are not aware of any exploit of this flaw." ); # https://curl.haxx.se/docs/adv_20170614.html script_set_attribute( attribute:"see_also", value:"https://curl.haxx.se/docs/CVE-2017-9502.html" ); # https://vuxml.freebsd.org/freebsd/9314058e-5204-11e7-b712-b1a44a034d72.html script_set_attribute( attribute:"see_also", value:"http://www.nessus.org/u?dea0e919" ); script_set_attribute(attribute:"solution", value:"Update the affected package."); script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P"); script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"); script_set_attribute(attribute:"plugin_type", value:"local"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:curl"); script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd"); script_set_attribute(attribute:"vuln_publication_date", value:"2017/06/14"); script_set_attribute(attribute:"patch_publication_date", value:"2017/06/15"); script_set_attribute(attribute:"plugin_publication_date", value:"2017/06/16"); 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:"FreeBSD Local Security Checks"); script_dependencies("ssh_get_info.nasl"); script_require_keys("Host/local_checks_enabled", "Host/FreeBSD/release", "Host/FreeBSD/pkg_info"); exit(0); } include("audit.inc"); include("freebsd_package.inc"); if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED); if (!get_kb_item("Host/FreeBSD/release")) audit(AUDIT_OS_NOT, "FreeBSD"); if (!get_kb_item("Host/FreeBSD/pkg_info")) audit(AUDIT_PACKAGE_LIST_MISSING); flag = 0; if (pkg_test(save_report:TRUE, pkg:"curl>=7.53.0<7.54.1")) flag++; if (flag) { if (report_verbosity > 0) security_warning(port:0, extra:pkg_report_get()); else security_warning(0); exit(0); } else audit(AUDIT_HOST_NOT, "affected");
NASL family Fedora Local Security Checks NASL id FEDORA_2017-03FC914348.NASL description Fixes CVE-2017-9502 (Windows builds only) 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 seen 2020-06-05 modified 2017-07-17 plugin id 101562 published 2017-07-17 reporter This script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/101562 title Fedora 26 : mingw-curl (2017-03fc914348) 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-2017-03fc914348. # include("compat.inc"); if (description) { script_id(101562); script_version("3.4"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04"); script_cve_id("CVE-2017-9502"); script_xref(name:"FEDORA", value:"2017-03fc914348"); script_name(english:"Fedora 26 : mingw-curl (2017-03fc914348)"); 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: "Fixes CVE-2017-9502 (Windows builds only) 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-2017-03fc914348" ); script_set_attribute( attribute:"solution", value:"Update the affected mingw-curl package." ); script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P"); script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"); script_set_attribute(attribute:"plugin_type", value:"local"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:mingw-curl"); script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:26"); script_set_attribute(attribute:"vuln_publication_date", value:"2017/06/14"); script_set_attribute(attribute:"patch_publication_date", value:"2017/06/21"); 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:"mingw-curl-7.54.1-1.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, "mingw-curl"); }
References
- http://openwall.com/lists/oss-security/2017/06/14/1
- http://openwall.com/lists/oss-security/2017/06/14/1
- http://www.securityfocus.com/bid/99120
- http://www.securityfocus.com/bid/99120
- http://www.securitytracker.com/id/1038697
- http://www.securitytracker.com/id/1038697
- https://curl.haxx.se/docs/adv_20170614.html
- https://curl.haxx.se/docs/adv_20170614.html