Vulnerabilities > CVE-2013-2061 - Information Exposure vulnerability in multiple products
Attack vector
NETWORK Attack complexity
HIGH Privileges required
NONE Confidentiality impact
PARTIAL Integrity impact
NONE Availability impact
NONE Summary
The openvpn_decrypt function in crypto.c in OpenVPN 2.3.0 and earlier, when running in UDP mode, allows remote attackers to obtain sensitive information via a timing attack involving an HMAC comparison function that does not run in constant time and a padding oracle attack on the CBC mode cipher.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Subverting Environment Variable Values The attacker directly or indirectly modifies environment variables used by or controlling the target software. The attacker's goal is to cause the target software to deviate from its expected operation in a manner that benefits the attacker.
- Footprinting An attacker engages in probing and exploration activity to identify constituents and properties of the target. Footprinting is a general term to describe a variety of information gathering techniques, often used by attackers in preparation for some attack. It consists of using tools to learn as much as possible about the composition, configuration, and security mechanisms of the targeted application, system or network. Information that might be collected during a footprinting effort could include open ports, applications and their versions, network topology, and similar information. While footprinting is not intended to be damaging (although certain activities, such as network scans, can sometimes cause disruptions to vulnerable applications inadvertently) it may often pave the way for more damaging attacks.
- Exploiting Trust in Client (aka Make the Client Invisible) An attack of this type exploits a programs' vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by placing themselves in the communication channel between client and server such that communication directly to the server is possible where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.
- Browser Fingerprinting An attacker carefully crafts small snippets of Java Script to efficiently detect the type of browser the potential victim is using. Many web-based attacks need prior knowledge of the web browser including the version of browser to ensure successful exploitation of a vulnerability. Having this knowledge allows an attacker to target the victim with attacks that specifically exploit known or zero day weaknesses in the type and version of the browser used by the victim. Automating this process via Java Script as a part of the same delivery system used to exploit the browser is considered more efficient as the attacker can supply a browser fingerprinting method and integrate it with exploit code, all contained in Java Script and in response to the same web page request by the browser.
- Session Credential Falsification through Prediction This attack targets predictable session ID in order to gain privileges. The attacker can predict the session ID used during a transaction to perform spoofing and session hijacking.
Nessus
NASL family Fedora Local Security Checks NASL id FEDORA_2013-7531.NASL description Fix for SSL vulnerability. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-03-17 modified 2013-05-16 plugin id 66452 published 2013-05-16 reporter This script is Copyright (C) 2013-2020 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/66452 title Fedora 18 : openvpn-2.3.1-2.fc18 (2013-7531) 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 2013-7531. # include("compat.inc"); if (description) { script_id(66452); script_version("1.8"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/12"); script_cve_id("CVE-2013-2061"); script_bugtraq_id(59672); script_xref(name:"FEDORA", value:"2013-7531"); script_name(english:"Fedora 18 : openvpn-2.3.1-2.fc18 (2013-7531)"); 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: "Fix for SSL vulnerability. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora 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://bugzilla.redhat.com/show_bug.cgi?id=960196" ); # https://lists.fedoraproject.org/pipermail/package-announce/2013-May/105609.html script_set_attribute( attribute:"see_also", value:"http://www.nessus.org/u?b58ca906" ); script_set_attribute( attribute:"solution", value:"Update the affected openvpn package." ); script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:P/I:N/A:N"); script_set_cvss_temporal_vector("CVSS2#E:ND/RL:OF/RC:C"); script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available"); script_set_attribute(attribute:"exploit_available", value:"false"); script_set_attribute(attribute:"plugin_type", value:"local"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:openvpn"); script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:18"); script_set_attribute(attribute:"patch_publication_date", value:"2013/05/07"); script_set_attribute(attribute:"plugin_publication_date", value:"2013/05/16"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2013-2020 Tenable Network Security, Inc."); 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 = eregmatch(pattern: "Fedora.*release ([0-9]+)", string:release); if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora"); os_ver = os_ver[1]; if (! ereg(pattern:"^18([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 18.x", "Fedora " + os_ver); if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item("Host/cpu"); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu); flag = 0; if (rpm_check(release:"FC18", reference:"openvpn-2.3.1-2.fc18")) flag++; if (flag) { if (report_verbosity > 0) security_note(port:0, extra:rpm_report_get()); else security_note(0); exit(0); } else { tested = pkg_tests_get(); if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested); else audit(AUDIT_PACKAGE_NOT_INSTALLED, "openvpn"); }
NASL family SuSE Local Security Checks NASL id SUSE_11_OPENVPN-131101.NASL description OpenVPN used a non-constant-time memcmp in HMAC comparison in openvpn_decrypt that might have allowed remote attackers to gain knowledge of plaintext data. (CVE-2013-2061) last seen 2020-06-05 modified 2013-11-29 plugin id 71137 published 2013-11-29 reporter This script is Copyright (C) 2013-2020 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/71137 title SuSE 11.3 Security Update : openvpn (SAT Patch Number 8493) code #%NASL_MIN_LEVEL 80502 # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from SuSE 11 update information. The text itself is # copyright (C) Novell, Inc. # if (NASL_LEVEL < 3000) exit(0); include("compat.inc"); if (description) { script_id(71137); script_version("1.2"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04"); script_cve_id("CVE-2013-2061"); script_name(english:"SuSE 11.3 Security Update : openvpn (SAT Patch Number 8493)"); script_summary(english:"Checks rpm output for the updated packages"); script_set_attribute( attribute:"synopsis", value:"The remote SuSE 11 host is missing one or more security updates." ); script_set_attribute( attribute:"description", value: "OpenVPN used a non-constant-time memcmp in HMAC comparison in openvpn_decrypt that might have allowed remote attackers to gain knowledge of plaintext data. (CVE-2013-2061)" ); script_set_attribute( attribute:"see_also", value:"https://bugzilla.novell.com/show_bug.cgi?id=843509" ); script_set_attribute( attribute:"see_also", value:"http://support.novell.com/security/cve/CVE-2013-2061.html" ); script_set_attribute(attribute:"solution", value:"Apply SAT patch number 8493."); script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:P/I:N/A:N"); script_set_attribute(attribute:"plugin_type", value:"local"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:11:openvpn"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:11:openvpn-auth-pam-plugin"); script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:suse_linux:11"); script_set_attribute(attribute:"patch_publication_date", value:"2013/11/01"); script_set_attribute(attribute:"plugin_publication_date", value:"2013/11/29"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2013-2020 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/cpu", "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)11") audit(AUDIT_OS_NOT, "SuSE 11"); if (!get_kb_item("Host/SuSE/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item("Host/cpu"); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if (cpu !~ "^i[3-6]86$" && "x86_64" >!< cpu && "s390x" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "SuSE 11", cpu); pl = get_kb_item("Host/SuSE/patchlevel"); if (isnull(pl) || int(pl) != 3) audit(AUDIT_OS_NOT, "SuSE 11.3"); flag = 0; if (rpm_check(release:"SLED11", sp:3, cpu:"i586", reference:"openvpn-2.0.9-143.40.5")) flag++; if (rpm_check(release:"SLED11", sp:3, cpu:"x86_64", reference:"openvpn-2.0.9-143.40.5")) flag++; if (rpm_check(release:"SLES11", sp:3, reference:"openvpn-2.0.9-143.40.5")) flag++; if (rpm_check(release:"SLES11", sp:3, reference:"openvpn-auth-pam-plugin-2.0.9-143.40.5")) flag++; if (flag) { if (report_verbosity > 0) security_note(port:0, extra:rpm_report_get()); else security_note(0); exit(0); } else audit(AUDIT_HOST_NOT, "affected");
NASL family Gentoo Local Security Checks NASL id GENTOO_GLSA-201311-13.NASL description The remote host is affected by the vulnerability described in GLSA-201311-13 (OpenVPN: Multiple vulnerabilities) Multiple vulnerabilities have been discovered in OpenVPN. Please review the CVE identifiers referenced below for details. Impact : A remote attacker may be able to recover plaintext from an encrypted communication. Another vulnerability could allow remote attacker perform a Man-in-the-Middle attack. Workaround : There is no known workaround at this time. last seen 2020-06-01 modified 2020-06-02 plugin id 70997 published 2013-11-21 reporter This script is Copyright (C) 2013-2018 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/70997 title GLSA-201311-13 : OpenVPN: Multiple vulnerabilities NASL family Amazon Linux Local Security Checks NASL id ALA_ALAS-2013-201.NASL description The openvpn_decrypt function in crypto.c in OpenVPN 2.3.0 and earlier, when running in UDP mode, allows remote attackers to obtain sensitive information via a timing attack involving an HMAC comparison function that does not run in constant time and a padding oracle attack on the CBC mode cipher. last seen 2020-06-01 modified 2020-06-02 plugin id 69759 published 2013-09-04 reporter This script is Copyright (C) 2013-2018 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/69759 title Amazon Linux AMI : openvpn (ALAS-2013-201) NASL family Fedora Local Security Checks NASL id FEDORA_2013-7552.NASL description Fix for SSL vulnerability. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-03-17 modified 2013-05-16 plugin id 66453 published 2013-05-16 reporter This script is Copyright (C) 2013-2020 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/66453 title Fedora 17 : openvpn-2.3.1-2.fc17 (2013-7552) NASL family Windows NASL id OPENVPN_2_3_1.NASL description According to its self-reported version number, the version of OpenVPN installed on the remote Windows host is prior to 2.3.1. It is, therefore, affected by an information disclosure vulnerability in the crypto.c component due to its HMAC comparison function not running in constant time. An unauthenticated, remote attacker can exploit this, via a timing attack, to disclose potentially sensitive information. last seen 2020-06-01 modified 2020-06-02 plugin id 125260 published 2019-05-17 reporter This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/125260 title OpenVPN < 2.3.1 Information Disclosure Vulnerability (Windows) NASL family Ubuntu Local Security Checks NASL id UBUNTU_USN-2368-1.NASL description It was discovered that OpenVPN incorrectly handled HMAC comparisons when running in UDP mode. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could possibly be used to perform a plaintext recovery attack. 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 seen 2020-06-01 modified 2020-06-02 plugin id 78041 published 2014-10-03 reporter Ubuntu Security Notice (C) 2014-2019 Canonical, Inc. / NASL script (C) 2014-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/78041 title Ubuntu 12.04 LTS : openvpn vulnerability (USN-2368-1) NASL family SuSE Local Security Checks NASL id OPENSUSE-2013-823.NASL description The following security issues were fixed : - Applied upstream patch changing to use a constant time memcmp when comparing HMACs in openvpn_decrypt to address ciphertext injection in UDP mode (CVE-2013-2061, bnc#843509). [0006-openvpn-2.0.9-HMAC-memcmp-CVE-2013-2061_bnc843509. patch] Changes in openvpn : - Applied upstream patch changing to use a constant time memcmp when comparing HMACs in openvpn_decrypt to address ciphertext injection in UDP mode (CVE-2013-2061, bnc#843509). [0006-openvpn-2.0.9-HMAC-memcmp-CVE-2013-2061_bnc843509. patch] last seen 2020-06-05 modified 2014-06-13 plugin id 75191 published 2014-06-13 reporter This script is Copyright (C) 2014-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/75191 title openSUSE Security Update : openvpn (openSUSE-SU-2013:1645-1) NASL family SuSE Local Security Checks NASL id SUSE_11_OPENVPN-131031.NASL description OpenVPN used a non-constant-time memcmp in HMAC comparison in openvpn_decrypt that might have allowed remote attackers to gain knowledge of plaintext data. (CVE-2013-2061) last seen 2020-06-05 modified 2013-11-29 plugin id 71136 published 2013-11-29 reporter This script is Copyright (C) 2013-2020 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/71136 title SuSE 11.2 Security Update : openvpn (SAT Patch Number 8496) NASL family Mandriva Local Security Checks NASL id MANDRIVA_MDVSA-2013-167.NASL description Updated openvpn package fixes security vulnerability : OpenVPN 2.3.0 and earlier running in UDP mode are subject to chosen ciphertext injection due to a non-constant-time HMAC comparison function. Plaintext recovery may be possible using a padding oracle attack on the CBC mode cipher implementation of the crypto library, optimistically at a rate of about one character per 3 hours. PolarSSL seems vulnerable to such an attack; the vulnerability of OpenSSL has not been verified or tested (CVE-2013-2061). last seen 2020-06-01 modified 2020-06-02 plugin id 66614 published 2013-05-28 reporter This script is Copyright (C) 2013-2019 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/66614 title Mandriva Linux Security Advisory : openvpn (MDVSA-2013:167) NASL family FreeBSD Local Security Checks NASL id FREEBSD_PKG_92F30415993511E2AD4C080027EF73EC.NASL description The OpenVPN project reports : OpenVPN 2.3.0 and earlier running in UDP mode are subject to chosen ciphertext injection due to a non-constant-time HMAC comparison function. last seen 2020-06-01 modified 2020-06-02 plugin id 65846 published 2013-04-08 reporter This script is Copyright (C) 2013-2018 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/65846 title FreeBSD : OpenVPN -- potential side-channel/timing attack when comparing HMACs (92f30415-9935-11e2-ad4c-080027ef73ec)
References
- http://lists.fedoraproject.org/pipermail/package-announce/2013-May/105568.html
- http://lists.fedoraproject.org/pipermail/package-announce/2013-May/105609.html
- http://lists.opensuse.org/opensuse-updates/2013-11/msg00012.html
- http://lists.opensuse.org/opensuse-updates/2013-11/msg00016.html
- http://www.mandriva.com/security/advisories?name=MDVSA-2013:167
- http://www.openwall.com/lists/oss-security/2013/05/06/6
- https://bugs.gentoo.org/show_bug.cgi?id=468756
- https://bugzilla.redhat.com/show_bug.cgi?id=960192
- https://community.openvpn.net/openvpn/wiki/SecurityAnnouncement-f375aa67cc
- https://github.com/OpenVPN/openvpn/commit/11d21349a4e7e38a025849479b36ace7c2eec2ee