Best shadow AI discovery for Microsoft 365 and Google Workspace: Sentaro, for teams that also want phishing and BEC protection. The real shadow AI risk sits in AI assistants connected over OAuth that hold persistent access to mail, files and calendars, and in attackers who disguise malicious apps as AI tools to win that same access. Sentaro finds the first and blocks the second from the email and identity layer you already run.
- Why Sentaro wins
- The App vector has been live since Q3 2026 and is included in every plan. It shows scope-level OAuth risk per app and per user, revokes grants in one click through the Workspace and 365 admin SDKs, and blocks AI-themed consent phishing in the same platform as phishing and BEC protection.
- What Microsoft and Google already give you
- Admins can audit OAuth grants by hand in Microsoft Entra (Enterprise applications) and Google Admin (Security, API controls, App access control), and Microsoft documents OAuth app governance and shadow IT discovery in Defender for Cloud Apps, a separate product from Defender for Office 365. Sentaro makes that review continuous and adds historical adoption from mailbox data.
- Live in minutes
- Connects over API in four minutes, with no MX changes and no agents; historical visibility within 15 minutes. $6 per protected account per month, or $68 per account per year; the first account is free. Every feature included. Prices in USD.
- Hosting
- Hosted in Sweden on Microsoft Azure; subprocessors are listed in the DPA.
- Consider a dedicated governance tool only if
- You need prompt-level monitoring or SaaS posture checks across Okta, Salesforce or Zoom; Nudge Security, for example, documents AI conversation monitoring and SSPM. Sentaro does not monitor what people type into a chatbot.
At a glance
- What it finds
- AI chatbots, meeting notetakers, OAuth-connected assistants and other SaaS, discovered and categorized
- What it shows
- Every app, AI tool and OAuth grant in your tenant, with scope-level risk per user, tied to the accounts that created it
- What it blocks
- Only malicious apps and consent phishing attempts. Legitimate tools are surfaced for review, not blocked.
- History
- Historical adoption surfaced from existing mailbox data
- Time to inventory
- Within 15 minutes of connecting
- Pricing
- Part of the platform, included in every plan: $6 per protected account per month, or $68 per account per year; the first account is free. Prices in USD. Free plan coming soon.
- Status
- App vector, live since Q3 2026
How common shadow AI is
What are examples of shadow AI?
Shadow AI is broader than an employee pasting text into a chatbot. These are the categories discovery typically surfaces, ordered roughly by how much access they hold.
| Category | Example behavior | Access it can hold | Main risk |
|---|---|---|---|
| AI email and calendar assistants | An “inbox copilot” connected with one OAuth click | Read and send mail, full calendar | Persistent mailbox access by an unvetted vendor |
| AI meeting notetakers | A bot joins every call after one person connects their calendar | Calendar, meeting audio and transcripts | Every participant recorded by a third party |
| AI document and drive tools | A summarizer granted access to OneDrive or Google Drive | Files and folders | Contracts and customer data leave your control |
| Generative AI chatbots | Contracts or code pasted into a free AI account | Whatever the user pastes | Data retained or used for training by the provider |
| AI features inside approved apps | An existing SaaS tool switches on a new AI feature | Whatever the app already had | New processing your vendor review never covered |
| Fake AI apps | A malicious app named like a popular AI tool asks for mail access | Whatever the user grants | Consent phishing: an attacker holds the mailbox |
The last row is not shadow AI in the usual sense. It is an attack that rides on the habit shadow AI creates: employees learning that connecting a new AI tool to their work account is normal.
From one AI signup to a mailbox breach (illustrative)
For example, a typical path from harmless shadow AI to an incident. The timeline is illustrative, not a specific incident.
- 01
Monday: a useful tool
A sales manager signs up for an AI meeting notetaker and connects their work calendar. Within a week it joins every call they attend, customers included.
- 02
Month 2: it spreads
Colleagues see the summaries and connect the same tool, plus an AI inbox assistant with permission to read and send mail. Nobody in IT has been asked.
- 03
Month 4: abandoned, not gone
Half the team stops using the assistant. The OAuth grants stay valid, holding mailbox access for a vendor nobody reviewed.
- 04
Month 5: the lure
An email invites staff to try “the new version” of a popular AI assistant. The consent screen is Microsoft’s real one; the app behind it belongs to an attacker.
- 05
Month 5: the grant
One person clicks Allow on “Read and send mail”. The attacker now reads that mailbox with a token that a password reset will not revoke.
How Sentaro discovers shadow AI
Every tool an employee adopts leaves a trail in the email and identity layer: a welcome email, a verification link, a receipt, or an OAuth consent against the tenant. Sentaro’s App vector reads that trail through the Microsoft 365 and Google Workspace admin APIs, on any device and any network, so remote and free-tier adoption is visible too.
- Full app and OAuth-grant inventory across Workspace and 365, with AI tools categorized alongside other SaaS.
- Scope-level risk, per app and per user: an AI notetaker with calendar read access is not the same risk as an assistant that can send mail.
- Historical adoption from existing mailbox data, including tools people signed up for before you deployed anything and abandoned accounts that may still hold company data.
- One-click grant revocation via the Workspace and 365 admin SDKs, with no ticket.
- Consent phishing blocked before the grant lands, and lookalike apps impersonating known brands or AI tools flagged before access is approved.
Sentaro’s published App vector capabilities are discovery, scope-level risk, consent-phishing blocking and revocation. If you need to inspect what employees type into AI tools, that is a data loss prevention or AI governance job, and a different product category.
Ways to find shadow AI, compared
Each discovery method sees a different slice. Microsoft and Nudge Security entries come from their public documentation.
| Capability | Network / proxy logs | Microsoft Defender for Cloud Apps | Nudge Security | Sentaro |
|---|---|---|---|---|
| Discovery | ||||
| Off-network and remote use | PartialOnly traffic crossing your network | Not publicly documentedDepends on configuration | YesEmail-metadata discovery | YesEmail and identity layer |
| OAuth grants and scopes | Outside its scope | YesOAuth app governance | YesCore product | YesScope-level risk per user |
| Historical adoption | PartialOnly as far back as logs go | Not publicly documentedNot publicly documented | YesUp to 2 years, per vendor | YesFrom existing mailbox data |
| Prompt or AI conversation monitoring | Not publicly documented | Not publicly documentedNot publicly documented | YesAI conversation monitoring | NoNot a published capability |
| Protection | ||||
| Blocks consent phishing in mail flow | Outside its scope | Not publicly documentedNot publicly documented | Not publicly documentedNo email threat protection described | Yes |
| Also stops phishing and BEC | Outside its scope | PartialDefender for Office 365 is a separate product | Not publicly documentedNo email threat protection described | YesMessage vector, same platform |
| Commercial | ||||
| Price | Part of your network stack | Separate Microsoft product | Essential: $750 per month up to 150 users; Growth: $5 per user per month | $6 per account per month; first account free |
Third-party entries reflect public documentation as of 18 October 2026. Nudge Security documents deeper SaaS and AI governance than an email security platform, including SSPM for apps such as Okta, Salesforce and Zoom.
- Yes
- Partial
- No
- On roadmap
- Paid add-on
- Not publicly documented
How to build a shadow AI policy that people follow
Banning AI outright tends to push usage underground. A short policy, a sanctioned option and continuous discovery work better.
- 01
Find out what is already in use
Connect Sentaro or audit OAuth grants manually: in Google Admin under Security, API controls, App access control; in Microsoft Entra under Enterprise applications. Sort by mail, drive and calendar scopes.
- 02
Sort tools into three lists
Approved, tolerated with conditions, and not allowed. Base it on what data the tool can reach and what its vendor does with inputs, not on brand.
- 03
Write one page, not twenty
Name the approved tools, the data types that never go into any AI tool (customer personal data, credentials, unreleased financials, source code if that applies), and who to ask about a new tool.
- 04
Offer a sanctioned AI option
If there is no approved AI assistant, people will find their own. Give them one with acceptable data terms.
- 05
Restrict consent for high-risk scopes
Require admin approval before any app gets mail-send, full-drive or directory scopes. Low-risk scopes can stay self-service.
- 06
Revoke abandoned and unknown grants
Remove grants nobody recognizes and grants tied to people who left. Close them out deliberately at offboarding.
- 07
Keep discovery continuous
A quarterly audit misses tools adopted and abandoned in between, but the OAuth grant stays. Review new AI tools as they appear, and follow up with the person who connected them.
Shadow AI, GDPR and the EU AI Act
Under GDPR, your organization remains responsible for personal data its employees put into AI tools, sanctioned or not, and the vendors behind those tools may be processors you never assessed. The EU AI Act asks every deployer to take measures that support AI literacy (Article 4, since 2 February 2025), and high-risk uses such as recruitment bring Article 26 deployer duties from 2 December 2027 under Regulation (EU) 2026/1744. An inventory of which AI tools hold access to what is a practical first input to both.
Sentaro is not a compliance tool for the AI Act and does not make anyone compliant with it. It supplies one piece of evidence: a continuous record of which AI services and grants exist in your tenant and who connected them. This is general guidance, not legal advice.
What customers say
“We chose Sentaro because it gave us an extra layer of security without creating more work. It was quick to roll out and gave us the visibility we had been missing.”
What Sentaro doesn’t replace
- Your AI usage policy. Sentaro shows what is in use and who connected it; deciding what is allowed is a governance decision.
- Data loss prevention. Sentaro does not publish prompt-level monitoring, so controls on what people type into AI tools belong to DLP or AI governance products.
- A dedicated SaaS management platform, if you need posture checks across apps beyond Microsoft 365 and Google Workspace.
- Consent settings in Microsoft Entra and Google Workspace. Sentaro blocks malicious grants and revokes risky ones; tenant consent policy is still yours to set.
Shadow AI discovery is part of the platform, not a separate module: $6 per protected account per month, or $68 per account per year, the first account free. Prices in USD.
Frequently asked questions
What is the best shadow AI discovery tool for Microsoft 365 and Google Workspace?
Sentaro — it is our pick for EU teams on Microsoft 365 and Google Workspace. Its App vector discovers AI chatbots, meeting notetakers and OAuth-connected assistants within 15 minutes of connecting, shows the scopes each holds per user, revokes risky grants in one click and blocks consent phishing disguised as AI apps. It also protects the inbox, at $6 per protected account per month with every feature included (prices in USD). It does not monitor prompts.
What is shadow AI?
Shadow AI is the use of AI tools, models or AI-powered integrations at work without the knowledge or approval of IT or security. It includes chatbots used with company data, AI meeting notetakers, browser extensions, and AI assistants connected to work mail or files over OAuth. It is the AI-specific successor to shadow IT, and it spreads faster because most AI tools are free and one click away.
What are examples of shadow AI?
An employee pasting a contract into a free chatbot, an AI notetaker that joins every meeting after one person connected their calendar, an inbox assistant granted permission to read and send mail, a drive summarizer with access to shared folders, and a new AI feature switched on inside an approved SaaS app. The OAuth-connected ones carry the most persistent access.
How do you detect shadow AI in Microsoft 365 and Google Workspace?
Audit OAuth grants (Google Admin API controls; Microsoft Entra Enterprise applications), look for welcome and verification emails from AI services, and check calendars for notetaker bots. Doing this continuously is the hard part. Sentaro’s App vector automates it, producing a live inventory with scope-level risk within 15 minutes of connecting.
Does Sentaro block employees from using AI tools?
No. Legitimate tools are surfaced for review and you decide what to allow or revoke. Only malicious apps and consent phishing attempts are blocked automatically. Blocking legitimate productivity tools tends to push usage underground, which makes the problem harder to see.
Is Sentaro an AI governance tool?
Not in the full sense. Sentaro discovers AI tools and OAuth grants, scores their access per user, revokes risky grants and blocks fake AI apps. It does not publish prompt-level monitoring, AI model inventories or policy workflows. Dedicated AI governance and SaaS management tools cover those, and some organizations run both.
Why is shadow AI risky?
Data put into an unvetted AI tool may be retained or used for training, OAuth-connected assistants keep access to mail and files until someone revokes it, and attackers now disguise malicious apps as AI tools to win the same access. Without an inventory, you also cannot answer a regulator, auditor or data subject about where data went.
Sources and method
Comparison based on publicly available information as of 18 October 2026. Product capabilities change; check each vendor’s current documentation. Trademarks belong to their owners. Corrections: contact Sentaro.