The Patching Friars' AlmanacA calendar of CVE saints

Patron of December 29

BiSecurHoly card for bisecur, generated with AI (Claude, Anthropic) for the Lunario dei Frati Patchatori.CC BY-NC-SA 4.0 BiSecur PORTA APERTA AUDITU
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Saint BiSecur, Who Opened Garages With a Single Whisper

Patron of automatic gates, remote controls that are all alike, and systems "as secure as online banking".

Life

On 29 December 2017, while the 34th Chaos Communication Congress was under way in Leipzig, CVE-2017-17910 made public what Markus Müllner and Markus Kammerstetter had found in Hörmann's BiSecur remotes for garages and gates. The AES encryption was well designed, but the random seed was never initialised: every remote they examined started from the same value. So listening to a single transmission with a cheap radio was enough to work out the key and clone the remote.

Prayer

O Saint BiSecur, guardian of garages, let our gates open only for those who hold the keys, not for those with good ears. Amen.

How to celebrate

Celebrated by replacing old transmitters with models made from 2018 on, and remembering that a strong algorithm cannot save a seed that never changes.

Technical record

Disclosed on
December 29 2017
CVE
CVE-2017-17910

On Hoermann BiSecur devices before 2018, a vulnerability can be exploited by recording a single radio transmission. An attacker can intercept an arbitrary radio frame exchanged between a BiSecur transmitter and a receiver to obtain the encrypted packet and the 32-bit serial number. The interception of the one-time pairing process is specifically not required. Due to use of AES-128 with an initial static random value and static data vector (all of this static information is the same across different customers' installations), the attacker can easily derive the utilized encryption key and decrypt the intercepted packet. The key can be verified by decrypting the intercepted packet and checking for known plaintext. Subsequently, an attacker can create arbitrary radio frames with the correct encryption key to control BiSecur garage and entrance gate operators and possibly other BiSecur systems as well ("wireless cloning"). To conduct the attack, a low cost Software Defined Radio (SDR) is sufficient. This affects Hoermann Hand Transmitter HS5-868-BS, HSE1-868-BS, and HSE2-868-BS devices.

Sources: nvd.nist.gov

Canonized by Pope EternalBlue I

Related saints

Same year: 2017

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