• TWEAK
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Alvorligt sikkerhedshul fundet i Linux

Et forskerteam har opdaget en ny sårbarhed, der påvirker de fleste Linux og Unix-lignende operativsystemer, herunder FreeBSD, OpenBSD, Android, iOS og macOS-systemer.

Fejlen tillader eksterne ”network adjacent attackere” at kapre og manipulere med VPN-forbindelser (Virtual Private Network) og injicere ondsindede data i TCP (Transmission Control Protocol) flowet.

I advarslen lyder det:

“I am reporting a vulnerability that exists on most Linux distros, and other *nix operating systems which allows a network adjacent attacker to determine if another user is connected to a VPN, the virtual IP address they have been assigned by the VPN server, and whether or not there is an active connection to a given website. Additionally, we are able to determine the exact seq and ack numbers by counting encrypted packets and/or examining their size. This allows us to inject data into the TCP stream and hijack connections,” reads the advisory published by the Breakpointing Bad researchers at the University of New Mexico”

Sårbarheden, kaldet CVE-2019-14899, kan udnyttes mod både IPv4 og IPv6 TCP streams.

Der rapporteres, at angrebet fungerer mod flere populære VPN-løsninger, herunder OpenVPN, IKEv2 / IPSec og WireGuard.

Forskerne tester også imod angreb mod Tor, eftersom det fungerer via SOCKS layer og implementerer godkendelsen og krypteringen, der finder sted i brugerområdet på omtalte.

“It should be noted, however, that the VPN technology used does not seem to matter and we are able to make all of our inferences even though the responses from the victim are encrypted, using the size of the packets and number of packets sent (in the case of challenge ACKs, for example) to determine what kind of packets are being sent through the encrypted VPN tunnel,” lyder det fra folkene bag opdagelsen.

Nedenfor er en liste over sårbare operativsystemer og init-systemer, der blev testet og udnyttet med succes af forskerne. De mener, at nedenstående liste vil udvides efterhånden som der graves i sikkerheden på flere systemer.

•Ubuntu 19.10 (systemd)

•Fedora (systemd)

• Debian 10.2 (systemd)

• Arch 2019.05 (systemd)

• Manjaro 18.1.1 (systemd)

• Devuan (sysV init)

• MX Linux 19 (Mepis+antiX)

• Void Linux (runit)

• Slackware 14.2 (rc.d)

• Deepin (rc.d)

• FreeBSD (rc.d)

• OpenBSD (rc.d)

“Most of the Linux dist

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