OpenVPN 2.5.1 and earlier versions allows a remote attackers to bypass authentication and access control channel data on servers configured with deferred authentication, which can be used to potentially trigger further information leaks.

The remote Debian 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the dla-2992 advisory.

  - OpenVPN versions before 2.3.3 and 2.4.x before 2.4.4 are vulnerable to a buffer overflow vulnerability     when key-method 1 is used, possibly resulting in code execution. (CVE-2017-12166)

  - An issue was discovered in OpenVPN 2.4.x before 2.4.9. An attacker can inject a data channel v2     (P_DATA_V2) packet using a victim's peer-id. Normally such packets are dropped, but if this packet arrives     before the data channel crypto parameters have been initialized, the victim's connection will be dropped.
    This requires careful timing due to the small time window (usually within a few seconds) between the     victim client connection starting and the server PUSH_REPLY response back to the client. This attack will     only work if Negotiable Cipher Parameters (NCP) is in use. (CVE-2020-11810)

  - OpenVPN 2.5.1 and earlier versions allows a remote attackers to bypass authentication and access control     channel data on servers configured with deferred authentication, which can be used to potentially trigger     further information leaks. (CVE-2020-15078)

  - OpenVPN 2.1 until v2.4.12 and v2.5.6 may enable authentication bypass in external authentication plug-ins     when more than one of them makes use of deferred authentication replies, which allows an external user to     be granted access with only partially correct credentials. (CVE-2022-0547)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote host is affected by the vulnerability described in GLSA-202105-25 (OpenVPN: Authentication bypass)

    It was discovered that OpenVPN incorrectly handled deferred       authentication.
  Impact :

    A remote attacker could bypass authentication and access control channel       data and trigger further information leaks.
  Workaround :

    Configure OpenVPN server to not use deferred authentication.

The version of openvpn installed on the remote host is prior to 2.4.11-1.48. It is, therefore, affected by a vulnerability as referenced in the ALAS-2021-1531 advisory.

  - OpenVPN 2.5.1 and earlier versions allows a remote attackers to bypass authentication and access control     channel data on servers configured with deferred authentication, which can be used to potentially trigger     further information leaks. (CVE-2020-15078)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES11 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2021:14723-1 advisory.

  - ** DISPUTED ** A cross-protocol scripting issue was discovered in the management interface in OpenVPN     through 2.4.5. When this interface is enabled over TCP without a password, and when no other clients are     connected to this interface, attackers can execute arbitrary management commands, obtain sensitive     information, or cause a denial of service (SIGTERM) by triggering XMLHttpRequest actions in a web browser.
    This is demonstrated by a multipart/form-data POST to http://localhost:23000 with a signal SIGTERM     command in a TEXTAREA element. NOTE: The vendor disputes that this is a vulnerability. They state that     this is the result of improper configuration of the OpenVPN instance rather than an intrinsic     vulnerability, and now more explicitly warn against such configurations in both the management-interface     documentation, and with a runtime warning. (CVE-2018-7544)

  - OpenVPN 2.5.1 and earlier versions allows a remote attackers to bypass authentication and access control     channel data on servers configured with deferred authentication, which can be used to potentially trigger     further information leaks. (CVE-2020-15078)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

This update for openvpn fixes the following issues :

  - CVE-2020-15078: Fixed authentication bypass with     deferred authentication (bsc#1185279).

  - CVE-2020-11810: Fixed race condition between allocating     peer-id and initializing data channel key (bsc#1169925).

  - CVE-2018-7544: Fixed cross-protocol scripting issue that     was discovered in the management interface     (bsc#1085803).

This update was imported from the SUSE:SLE-15:Update update project.

This update for openvpn fixes the following issues :

CVE-2020-15078: Fixed authentication bypass with deferred authentication (bsc#1185279).

CVE-2018-7544: Fixed cross-protocol scripting issue that was discovered in the management interface (bsc#1085803).

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for openvpn fixes the following issues :

CVE-2020-15078: Fixed authentication bypass with deferred authentication (bsc#1185279).

CVE-2020-11810: Fixed race condition between allocating peer-id and initializing data channel key (bsc#1169925).

CVE-2018-7544: Fixed cross-protocol scripting issue that was discovered in the management interface (bsc#1085803).

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote Ubuntu 18.04 LTS / 20.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4933-1 advisory.

    It was discovered that OpenVPN incorrectly handled certain data channel v2 packets. A remote attacker     could possibly use this issue to inject packets using a victim's peer-id. This issue only affected Ubuntu     18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-11810)

    It was discovered that OpenVPN incorrectly handled deferred authentication. When a server is configured to     use deferred authentication, a remote attacker could possibly use this issue to bypass authentication and     access control channel data. (CVE-2020-15078)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Gert Doring reports :

OpenVPN 2.5.1 and earlier versions allows a remote attackers to bypass authentication and access control channel data on servers configured with deferred authentication, which can be used to potentially trigger further information leaks.

ID	Name	Product	Family	Severity
160475	Debian DLA-2992-1 : openvpn - LTS security update	Nessus	Debian Local Security Checks	critical
157011	GLSA-202105-25 : OpenVPN: Authentication bypass	Nessus	Gentoo Local Security Checks	high
153165	Amazon Linux AMI : openvpn (ALAS-2021-1531)	Nessus	Amazon Linux Local Security Checks	high
150543	SUSE SLES11 Security Update : openvpn-openssl1 (SUSE-SU-2021:14723-1)	Nessus	SuSE Local Security Checks	critical
149641	openSUSE Security Update : openvpn (openSUSE-2021-734)	Nessus	SuSE Local Security Checks	critical
149461	SUSE SLES12 Security Update : openvpn (SUSE-SU-2021:1576-1)	Nessus	SuSE Local Security Checks	critical
149458	SUSE SLED15 / SLES15 Security Update : openvpn (SUSE-SU-2021:1577-1)	Nessus	SuSE Local Security Checks	critical
149252	Ubuntu 18.04 LTS / 20.04 LTS : OpenVPN vulnerabilities (USN-4933-1)	Nessus	Ubuntu Local Security Checks	high
148928	FreeBSD : openvpn -- deferred authentication can be bypassed in specific circumstances (efb965be-a2c0-11eb-8956-1951a8617e30)	Nessus	FreeBSD Local Security Checks	high

Detections

Analytics

CVE-2020-15078

high

Tenable Plugins

critical

high

high

critical

critical

critical

critical

high

high