services / Azure / Virtual network

An Azure virtual network (VNet) is the fundamental L3 network-isolation boundary in Azure, defining the address space, subnets, peerings, and security policy scope for all resources deployed into it.

The VNet is the primary network-segmentation boundary in Azure; control-plane privileges on it — altering peerings, address space, or security-group associations, or attaching unauthorized resources into it — can enable significant privilege escalation via lateral network access (per the CRITICAL definition in services/README.md).

Microsoft.​Network/​virtualNetworks/​peer/​action

Peers the VNet with another VNet, bridging the two address spaces. Lets an attacker who controls a separate (e.g. lower-trust or attacker-owned) VNet bridge it directly into this one, extending network reachability across a segmentation boundary that was meant to isolate the two environments.

Risks

1. Lateral movement (BOOST)
2. Network movement (BOOST)

Scope: CRITICAL

This privilege may grant access to sensitive data from a significant fraction of organizational functions, allow interruption of critical organizational services, or its exploit could lead to significant privilege escalation.

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