A group of white hat hackers collaborated with SCRT Labs to fix a flaw that could have removed the anonymity of the Secret Network blockchain entirely. While fixes have since been made, the potential fragility of the privacy of this type of network must be questioned.
Secret Network may no longer be anonymous
A group of white hats hackers have revealed a flaw to the SCRT Labs team, in charge of developing the Secret Network anonymous blockchain (SCRT). This flaw theoretically allowed the network’s confidentiality to be cancelled by de-anonymising all transactions retroactively.
In reality, this vulnerability was reported on October 3rd and immediate action was taken. SCRT Labs chose to delay its communication to allow the matter to be dealt with in depth, without risking the opportunity for a malicious actor to take advantage of the flaw before a full solution was available.
The flaw was not specific to the Secret Network, but resided in Intel processors used by some of the network’s nodes. More precisely, it affected an extension called Software Guard Extensions (SGX), which was supposed to protect the data of the software used.
To keep it simple, a malicious actor could, under certain conditions, have broken the confidentiality of the data of a blockchain history saved on a vulnerable node, and thus lifted the anonymity by recovering the main decryption key:
We evaluated TEE-based blockchain Secret Network to see if it was susceptible to AepicLeak, and ended up finding the master decryption key for the whole network. Read more and see a testnet demo at https://t.co/coe7EPXmrY https://t.co/E2pcoNSEsz
– Andrew Miller (@socrates1024) November 29, 2022
SCRT Labs worked with Intel and researchers to develop an update that prevents any vulnerable machine from operating a Secret Network node.
To “limit the attack surface”, SCRT Labs has since also restricted access to network participation to so-called “server class” hardware only. In addition, the teams promise to focus on more security-related features:
” This will allow network stakeholders to deal with any similar future vulnerabilities even more quickly, as well as giving nodes tools to self-check. It is important to note here that at no time were the funds of network users at risk from this vulnerability, nor was it the fault of the Secret Network. It was the anonymity of the blockchain that was affected, which is supposed to be the fundamental pillar of the network. As far as SCRT Labs is aware, the flaw has not been exploited in real life conditions, although in truth there is no formal guarantee of this.
This case suggests that no matter how willing a project is to create a confidential network, it may never be confidential forever, as technical means advance or vulnerabilities are identified.
