CVE-2020-11810

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.

OpenVPN is a full-featured open source SSL VPN solution that accommodates a wide range of configurations, including remote access, site-to-site VPNs, Wi-Fi security, and enterprise-scale remote access solutions with load balancing, failover, and fine-grained access-controls. Starting with the fundamental premise that complexity is the enemy of security, OpenVPN offers a cost-effective, lightweight alternative to other VPN technologies that is well-adapted for the SME and enterprise markets.

Security Fix(es):

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)

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.

Updated openvpn packages fix security vulnerability:

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).

The openvpn package has been updated to version 2.4.9, fixing the issue and other bugs. See the upstream release notes for details.

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.

These are all security issues fixed in the openvpn-2.5.3-1.2 package on the GA media of openSUSE Tumbleweed.

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).

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)