We’re pleased to share a security enhancement for Ubuntu workloads on Microsoft Azure. In collaboration with Microsoft, Ubuntu now supports Azure’s Metadata Security Protocol (MSP)—a feature that hardens access to the Instance Metadata Service (IMDS) and WireServer. On Ubuntu, MSP is enabled by the azure-proxy-agent package, Canonical’s integration of Microsoft’s Guest Proxy Agent (GPA).Why MSP raises the baselineTraditional metadata endpoints are default-open within a VM. That leaves room for confused-deputy/SSRF paths and sandbox escapes. MSP flips this to default-closed with strong controls at the metadata boundary:Strong authentication. IMDS/WireServer accept only requests endorsed (HMAC-signed) by a trusted in-guest delegate (GPA/azure-proxy-agent). Unsigned traffic is rejected.Identity-aware authorization. The agent uses eBPF to intercept IMDS and WireServer requests and identify the originating process and user. It then checks an allowlist before endorsing the request (granular, per-endpoint RBAC).Safe by default. Even if guest firewall rules are misconfigured or bypassed, unauthenticated traffic still cannot reach the metadata services.For architecture and Azure-side configuration, see Microsoft’s MSP documentation.MSP must be enabled in Azure. Installing the Ubuntu package alone does not turn on MSP. Enable MSP for the VM/VMSS from the Azure side (Portal/CLI/template) so requests are validated and unsigned traffic is rejected.Availability and roadmapThe azure-proxy-agent package is available now for testing and is in the development series for Ubuntu 25.10 “Questing Quokka.”After we incorporate feedback and verify stability, we plan to deliver azure-proxy-agent to Ubuntu 25.04 (Plucky Puffin), Ubuntu 24.04 LTS (Noble Numbat) and Ubuntu 22.04 LTS (Jammy Jellyfish) through the Stable Release Updates (SRU) process.Early testing on LTSFor Ubuntu 24.04 LTS and 22.04 LTS, azure-proxy-agent is currently available in -proposed. If you’re comfortable testing SRU candidates, enable -proposed temporarily and pin only this package so you don’t upgrade unrelated components. Background on -proposed and SRUs: Stable Release UpdatesGeneric, codename-aware snippet (works for Jammy/Noble/Plucky):# Resolve codename (prefers /etc/os-release; falls back to lsb_release)CODENAME="$(. /etc/os-release 2>/dev/null; echo ${VERSION_CODENAME:-$(lsb_release -cs)})"# Pin only azure-proxy-agent from -proposedsudo tee /etc/apt/preferences.d/azure-proxy-agent