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Bare Metal Attack scenarios
Live RAM extraction
@@ -192,21 +231,21 @@ in this post we are going to do a threat modelling exercise:
Bob powers down the serve hosting the vps and extracts its RAM, refrigerate it to analyze its contents
Countermeasures
- This one is very tricky and can't be addressed without renting a bare-metal server instead. Alice would need hardware that supports RAM encryption (such as AMD SEV and SME).
+ Alice would need hardware that supports RAM encryption (such as AMD SEV and SME).
- This attack is both costly and obvious as it requires the server to go offline. Alice's decides to accept the risk for now and reevaluate based on the evolving sensitivity of the data stored on her VPS.
+ This attack is both costly and obvious as it requires the server to go offline. Alice's decides to accept the risk for now and reevaluate based on the evolving sensitivity of the data stored on her server.
BMC Exploitation
Attack
A malicious firmware update is deployed to the Baseboard Management Controller (BMC), providing stealthy persistent access and enabling future compromise of the OS or hypervisor.
Countermeasures
- This attack has the same issue as the previous one and could be deployed during a schedule maintenance at Bob's datacenter even if Alice was using a baremetal. If she were to migrate to such a setup, then ensuring a TPM is present on the motheboard and only signed firmware updates are accepted would be a first step. This wouldn't protect her from a malicious update signed with a legitimate key as some government agency could deploy.
+ This attack has the same issue as the previous one and could be deployed during a schedule maintenance at Bob's datacenter. Ensuring a TPM is present on the motheboard and only signed firmware updates are accepted is a first step. This wouldn't protect her from a malicious update signed with a legitimate key as some government agency could deploy. Another, better option is to opt for a physical enclosure only she can access in the datacenter and be present during maintenance. Such enclosure would need to be monitored and trigger a server poweroff in case of breach.
Evil Maid Attack
Attack
With physical access to the server, a rogue technician could inject a rootkit into the UEFI to mainain persistance, running their code before the OS loads.
Countermeasures
- A baremetal server in a physically locked enclosure such as ones used by payment processors in their datacenters would greatly reduce the likelihood of this attack. Again, Alice deems the current sensitivity of her data not sufficient to justify the costs.
+ A physically locked enclosure such as ones used by payment processors in their datacenters would greatly reduce the likelihood of this attack.
@@ -215,7 +254,8 @@ in this post we are going to do a threat modelling exercise: