CVE-2025-62550: Azure Monitor Agent RCE Vulnerability

CVE-2025-62550 Overview

CVE-2025-62550 is an out-of-bounds write vulnerability in Microsoft Azure Monitor Agent. An authorized attacker can exploit the flaw over a network to execute arbitrary code on the affected host. Microsoft published the advisory on December 9, 2025, and the issue is tracked under [CWE-787] (Out-of-bounds Write) and [CWE-131] (Incorrect Calculation of Buffer Size).

The vulnerability requires low-level privileges but no user interaction, and impacts confidentiality, integrity, and availability of the agent host. Azure Monitor Agent is widely deployed across virtual machines, scale sets, and Arc-enabled servers, expanding the potential blast radius.

Critical Impact
A network-reachable authenticated attacker can corrupt memory in Azure Monitor Agent and execute code in the agent's process context, enabling lateral movement across Azure and hybrid infrastructure.

Affected Products

Microsoft Azure Monitor Agent (Windows builds)
Microsoft Azure Monitor Agent (Linux builds)
Azure Monitor Agent on Arc-enabled servers and Azure VM Scale Sets

Discovery Timeline

2025-12-09 - CVE-2025-62550 published to NVD
2025-12-10 - Last updated in NVD database

Technical Details for CVE-2025-62550

Vulnerability Analysis

The flaw is an out-of-bounds write in Azure Monitor Agent triggered when the agent processes attacker-controlled telemetry or configuration data received over the network. Memory beyond the bounds of an allocated buffer can be modified, allowing corruption of adjacent structures.

The weakness is classified under [CWE-787] for the out-of-bounds write and [CWE-131] for incorrect buffer size calculation. The combination indicates that a size computation upstream of a write operation does not correctly account for input length, producing a buffer smaller than the data written into it.

Successful exploitation yields code execution in the agent's process context. Azure Monitor Agent runs with elevated privileges on host systems, so attacker code inherits broad access to local telemetry pipelines, managed identity tokens, and Log Analytics configuration.

Root Cause

The root cause is an incorrect buffer length calculation during deserialization or parsing of network-delivered data inside the agent. The undersized allocation produces a write past the buffer boundary when the agent copies the full payload into memory.

Attack Vector

Exploitation requires network reachability to the Azure Monitor Agent and a valid set of low-privilege credentials. The attacker submits a crafted payload that triggers the malformed length calculation. No user interaction is required. The vulnerability scope is unchanged, meaning code execution remains within the agent's security context but supports follow-on privilege escalation and lateral movement.

No public proof-of-concept exploit code has been published. Microsoft has not reported in-the-wild exploitation, and the CVE is not listed in the CISA Known Exploited Vulnerabilities catalog. See the Microsoft CVE-2025-62550 Advisory for vendor-confirmed technical details.

Detection Methods for CVE-2025-62550

Indicators of Compromise

Unexpected crashes, restarts, or watchdog events for the AzureMonitorAgent service or MonAgentCore process
Anomalous outbound network connections originating from the Azure Monitor Agent process to non-Microsoft endpoints
New child processes spawned by the agent, including shells, scripting interpreters, or LOLBins
Modifications to agent configuration directories or unexpected DLL/.so files loaded into the agent process

Detection Strategies

Monitor process integrity for Azure Monitor Agent binaries and alert on unsigned modules loaded into the agent
Apply behavioral detections for memory corruption indicators such as exception records followed by code execution patterns
Correlate agent crash telemetry with inbound network connections to identify exploitation attempts
Hunt for managed identity token requests originating from unusual times or sequences after agent process anomalies

Monitoring Recommendations

Forward Azure Monitor Agent diagnostic logs and Windows/Linux audit logs to a central analytics platform
Track installed agent versions across the fleet and alert on hosts that lag behind the patched build
Enable Microsoft Defender for Cloud recommendations for outdated agent extensions and act on advisor findings

How to Mitigate CVE-2025-62550

Immediate Actions Required

Apply the Microsoft-supplied Azure Monitor Agent update referenced in the Microsoft CVE-2025-62550 Advisory to all Windows, Linux, and Arc-enabled hosts
Inventory all VMs, scale sets, and Arc machines running Azure Monitor Agent and confirm extension auto-upgrade is enabled
Restrict network access to the agent's management endpoints using Network Security Groups and private link where supported
Rotate credentials and managed identity secrets associated with hosts that show signs of agent compromise

Patch Information

Microsoft has released a fixed version of Azure Monitor Agent. Customers using the Azure Monitor Agent VM extension with automatic minor version upgrades enabled receive the patch automatically. Hosts with pinned versions or air-gapped/Arc-enabled deployments require manual upgrade. Refer to the Microsoft CVE-2025-62550 Advisory for the exact patched build number and per-platform download paths.

Workarounds

Enable automatic extension upgrades for Azure Monitor Agent across all subscriptions and management groups
Limit which identities can authenticate to the agent's network surface using Azure RBAC and conditional access
Where patching is delayed, isolate agent hosts from untrusted networks and enforce just-in-time administrative access

bash

# Enable automatic extension upgrade for Azure Monitor Agent on a Linux VM
az vm extension set \
  --resource-group <rg-name> \
  --vm-name <vm-name> \
  --name AzureMonitorLinuxAgent \
  --publisher Microsoft.Azure.Monitor \
  --enable-auto-upgrade true

# Verify the currently installed version
az vm extension show \
  --resource-group <rg-name> \
  --vm-name <vm-name> \
  --name AzureMonitorLinuxAgent \
  --query "typeHandlerVersion"