u/jaivibi

Been seeing FileMalwareDetected events pop up in Purview audit logs lately for files that are clearly clean, and, it got me thinking about how many people actually know how to investigate these properly vs just dismissing them. Worth flagging upfront: if you're seeing a spike in these right now, it may not be purely noise. CVE-2026-32201, a SharePoint spoofing vuln that was actively exploited and patched on April 14, was causing improper input validation issues that triggered false audit flags. CISA added it to the KEV catalog, so if you haven't patched yet, that's the first thing to do. Some of what looks like a false positive wave in your logs could be related, to that or to the RCE activity that's been generating audit noise since earlier this year. That said, the usual culprits are still very much a thing. OneDrive sync clients triggering scan activity that looks suspicious, third-party apps accessing content in patterns that, set off the detection engine, and signature-based scanning flagging benign files with embedded macros or unusual compression. All still common. When I dig into these, the first stop is always Purview Audit. Filter for FileMalwareDetected and pull the AuditData field. You'll get VirusVendor, VirusInfo, the file path, and site URL, which is usually enough to figure out whether it's a real hit or noise. VirusVendor showing "Default" means signature-based detection, "Advanced Threat Protection" means Safe Attachments caught it, and those I take more seriously. You can also run Get-SPOMalwareFile in PowerShell if you want to pull this programmatically rather than clicking through the portal. One thing to keep in mind: audit log retention in Purview varies by license, so, confirm your tenant settings before assuming you have the full 180 days to work with. If it does look like a false positive, submit through aka.ms/wdsi so Microsoft can update their detection. Cross-referencing timestamps and IPs in Defender for Cloud Apps also helps figure out whether the access pattern makes sense for a real user vs automated tooling. The thing that frustrates me is that with tool sprawl across multiple DLP policies and third-party scanners, the noise compounds fast, especially during a period like right now

Securiti published a guide framing overprivileged access as a systemic risk rather than just a misconfiguration problem. The core argument is that both human accounts and machine identities routinely accumulate permissions well beyond what their actual, job function requires, and that traditional IAM tooling wasn't built to catch this at scale across hybrid and SaaS environments. Not a groundbreaking claim, but the framing around AI copilots specifically is worth paying attention to. When an AI agent inherits a user's effective permissions, the blast radius of that access suddenly matters, a lot more than it did when it was just a person occasionally clicking around a file share.

The visibility gap they're describing is real. Most orgs I've talked to have decent identity governance on paper but almost no insight into what data those identities can actually reach. There's a difference between "this account has read access to Finance" and "this account can read, 40,000 files including everything in the unclassified M&A folder." Tools in this space approach that problem differently. Purview gives you some of this natively if you're all-in on M365, though your mileage may vary depending on, how hybrid your infrastructure is or whether you need to tie access findings back to PAM and IGA context. Netwrix offers data access governance tools with a focus on permissions mapping that can be useful in complex environments. Others like Forcepoint's DSPM incorporate classification into their workflows in various ways.

One thing worth keeping in mind is that a significant chunk of organizations are still running hybrid IT, which, means the clean cloud-native governance story most vendors pitch doesn't apply to the majority of environments actually dealing with this. The Securiti guide is vendor-agnostic enough to be useful regardless of your stack. If your org is starting to think seriously about AI agent access and you haven't, audited what those agents can actually touch, that's probably the right place to start reading.

The 2025 Zscaler ThreatLabz VPN Risk Report got some attention in security circles, but one thing, it quietly reinforces is how much overprovisioned remote access compounds the risk once someone is in. VPN gets you through the door, but what's sitting exposed on SharePoint after that is often the real story.

Anyway, that sent me back through a bunch of resources I've collected over the past year specifically around SharePoint permissions auditing. Sharing here because I've never seen a good consolidated list for this sub.

What's in the list:

Microsoft's own effective permissions checker (buried in site settings, most people miss it) The SharePoint PnP PowerShell module, specifically Get-PnPPermissions, which can dump site/list/item level permissions recursively AvePoint's free permissions audit report tool (generates a readable export, useful for showing data owners what they actually own) Microsoft Purview's data access, reports if you're on E5, not perfect but covers a lot of ground for OneDrive and SharePoint For orgs with hybrid file server and SharePoint sprawl, tools like Netwrix Data Access Governance can resolve effective permissions across both environments including broken inheritance chains, which is where things usually get ugly

The broken inheritance problem specifically is what makes SharePoint so painful. Someone shares a folder with unique permissions in 2021, the site gets reorganized, and three years later nobody, knows that subfolder is still wide open to a group that includes former contractors who left long ago. The PnP script above surfaces most of that if you run it at item level, but it takes time to process on large libraries.

If anyone has other scripts or tools they've actually used in production I'd add them to my notes. The more the better for this kind of thing.

The recent Microsoft Purview updates (there's been some movement around data quality scanning previews and Data Security Posture features, though it's worth, checking what's actually hit GA versus still being in preview) got me thinking about how fragmented this space is depending on your setup. If you're running a homelab that's grown past "just for fun" and actually stores things, like family medical docs, tax records, or small business files, the tooling choices get surprisingly different.

On the lighter end you've got tools like Lldap or Authelia handling authentication, which is great, but they don't really, tell you who has access to what file share or whether a permission you set 18 months ago is still appropriate. For that layer, people tend to reach for one of a few approaches. Nextcloud's built-in audit log is decent if everything lives there. If you're mixing Samba shares, a NAS, and maybe a self-hosted Gitea instance, you, end up stitching together rsyslog parsing or something custom just to get a coherent picture.

On the enterprise side of the comparison, tools like Varonis and Netwrix Data Access Governance are, built exactly for this problem across hybrid environments, though they're clearly scoped for organizations rather than homelabs. The Purview updates are interesting because they push Microsoft's native tooling closer to what those platforms do, but it's, still pretty M365-centric and doesn't help much if your sensitive data lives on a Linux NFS mount or a Synology.

For most homelab setups with actual sensitive data, the practical middle ground I've landed on is OpenLDAP or Lldap for identity, strict group-based, Samba share permissions audited manually every quarter, and something like Graylog or Loki to centralize access logs so you can at least search them. Not perfect, but it's the closest thing to a coherent audit trail without paying enterprise licensing fees or running a full SIEM.

The Purview stuff is worth watching if you're already in the Microsoft ecosystem, but it's not really moving the needle for people running mixed self-hosted stacks.

Been setting this up in our tenant lately and it's actually pretty solid once you understand what's happening under the hood. When you add a SharePoint library as a knowledge source in Copilot Studio, the agent, queries on behalf of the signed-in user, so it respects whatever permissions that person already has. Someone without access to a restricted library won't get content surfaced from it. That part works as advertised. Where it gets tricky is with oversharing. If your library permissions are already a mess (and honestly whose aren't), the agent will just inherit that mess. It doesn't clean anything up. So if half your org has read access to something they probably shouldn't, the agent will happily surface that content to them. Sensitivity labels and DLP through Purview help here but only if you've actually set those up properly beforehand. Also worth knowing there's a 20 source limit per agent and file size caps depending on your license tier, so for bigger setups you'll hit walls pretty fast. The other thing I've run into is restricted lists being a pain. Direct access sometimes throws errors with private content so there's a workaround floating around using, Power Automate to generate filtered PDFs dynamically instead of pointing the agent straight at the list. Bit clunky but it works. Curious if anyone else has found a cleaner way to handle that, or if you've run, into the indexing lag issue with larger libraries where the agent is pulling slightly stale content.