Vulnerabilities > CVE-2018-16758 - Missing Authentication for Critical Function vulnerability in multiple products
Attack vector
NETWORK Attack complexity
HIGH Privileges required
NONE Confidentiality impact
HIGH Integrity impact
NONE Availability impact
NONE Summary
Missing message authentication in the meta-protocol in Tinc VPN version 1.0.34 and earlier allows a man-in-the-middle attack to disable the encryption of VPN packets.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Choosing a Message/Channel Identifier on a Public/Multicast Channel Attackers aware that more data is being fed into a multicast or public information distribution means can 'select' information bound only for another client, even if the distribution means itself forces users to authenticate in order to connect initially. Doing so allows the attacker to gain access to possibly privileged information, possibly perpetrate other attacks through the distribution means by impersonation. If the channel/message being manipulated is an input rather than output mechanism for the system, (such as a command bus), this style of attack could change its identifier from a less privileged to more so privileged channel or command.
- Using Unpublished Web Service APIs An attacker searches for and invokes Web Services APIs that the target system designers did not intend to be publicly available. If these APIs fail to authenticate requests the attacker may be able to invoke services and/or gain privileges they are not authorized for.
- Manipulating Writeable Terminal Devices This attack exploits terminal devices that allow themselves to be written to by other users. The attacker sends command strings to the target terminal device hoping that the target user will hit enter and thereby execute the malicious command with their privileges. The attacker can send the results (such as copying /etc/passwd) to a known directory and collect once the attack has succeeded.
- Cross Site Request Forgery (aka Session Riding) An attacker crafts malicious web links and distributes them (via web pages, email, etc.), typically in a targeted manner, hoping to induce users to click on the link and execute the malicious action against some third-party application. If successful, the action embedded in the malicious link will be processed and accepted by the targeted application with the users' privilege level. This type of attack leverages the persistence and implicit trust placed in user session cookies by many web applications today. In such an architecture, once the user authenticates to an application and a session cookie is created on the user's system, all following transactions for that session are authenticated using that cookie including potential actions initiated by an attacker and simply "riding" the existing session cookie.
Nessus
NASL family FreeBSD Local Security Checks NASL id FREEBSD_PKG_A4EB38EACC0611E8ADA4408D5CF35399.NASL description tinc-vpn.org reports : The authentication protocol allows an oracle attack that could potentially be exploited. If a man-in-the-middle has intercepted the TCP connection it might be able to force plaintext UDP packets between two nodes for up to a PingInterval period. last seen 2020-06-01 modified 2020-06-02 plugin id 118024 published 2018-10-10 reporter This script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/118024 title FreeBSD : tinc -- Buffer overflow (a4eb38ea-cc06-11e8-ada4-408d5cf35399) NASL family Fedora Local Security Checks NASL id FEDORA_2018-AFAE5E8438.NASL description Security fix for CVE-2018-16737, CVE-2018-16738, CVE-2018-16758 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 2019-01-03 plugin id 120712 published 2019-01-03 reporter This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/120712 title Fedora 29 : tinc (2018-afae5e8438) NASL family Fedora Local Security Checks NASL id FEDORA_2018-31C2A0B2EA.NASL description Security fix for CVE-2018-16737, CVE-2018-16738, CVE-2018-16758 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 2019-01-03 plugin id 120335 published 2019-01-03 reporter This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/120335 title Fedora 28 : tinc (2018-31c2a0b2ea) NASL family Debian Local Security Checks NASL id DEBIAN_DSA-4312.NASL description Several vulnerabilities were discovered in tinc, a Virtual Private Network (VPN) daemon. The Common Vulnerabilities and Exposures project identifies the following problems : - CVE-2018-16738 Michael Yonli discovered a flaw in the implementation of the authentication protocol that could allow a remote attacker to establish an authenticated, one-way connection with another node. - CVE-2018-16758 Michael Yonli discovered that a man-in-the-middle that has intercepted a TCP connection might be able to disable encryption of UDP packets sent by a node. last seen 2020-06-01 modified 2020-06-02 plugin id 117958 published 2018-10-09 reporter This script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/117958 title Debian DSA-4312-1 : tinc - security update