I set up a quick demonstration to show risks of curl|bash and how a bad-actor could potentially hide a malicious script that appears safe.
It’s nothing new or groundbreaking, but I figure it never hurts to have another reminder.
I set up a quick demonstration to show risks of curl|bash and how a bad-actor could potentially hide a malicious script that appears safe.
It’s nothing new or groundbreaking, but I figure it never hurts to have another reminder.
This is incorrect. If the update you download is compromised then the signature is invalid and the update fails.
To achieve a compromised update you either need to compromise the update infrastructure AND the key or the infratstructure AND exploit the local updater to accept the invalid or forged signature.
If I can control your infra I can alter what is a valid signature. It has happened. It will happen again. Digital signatures are not sufficient by themselves to prevent supply chain risks. Depending on your threat model, you need to assume advanced adversaries will seek to gain a foothold in your environment by attacking your software supplier. in these types of attacks threat actors can and will take control over the distribution mechanisms deploying trojaned backdoors as part of legitimately signed updates. It is a complex problem and I highly encourage you to read the NIST guidance to understand just how deep the rabbit hole goes.
Cybersecurity Supply Chain Risk Management Practices for Systems and Organizations
No you cannot, the pub key either needs to be present on the updater or uses infrastructure that is not owned by you. Usually how most software suppliers are doing it the public key is supplied within the updater.