By Sergiu Gatlan September 27, 2022 03:11 PM
Microsoft announced today that it will retire Client Access Rules (CARs) in Exchange Online within a year, by September 2023.

Microsoft also recently warned customers that it would start disabling basic authentication in random tenants to improve Exchange Online security beginning October 1, 2022.

CARs are sets of conditions, exceptions, actions, and priority values that allow Microsoft 365 admins to filter client access to Exchange Online based on many factors.

Connections can be allowed or blocked based on the client’s IP addresses and authentication type, as well as the protocol, application, or service they’re using to connect.

In short, once configured, they help control who can access what resources in an Exchange Online organization.

“Today, we are announcing the retirement of CARs in Exchange Online, to be fully deprecated by September 2023,” the Exchange Team said.

“We will send Message Center posts to tenants using client access rules to start the planning process to migrate their rules.”

The company will begin the deprecation process by first disabling client access rules in tenants where they’re unused starting October 2022.

Until September 2023, Microsoft plans to help migrate all remaining tenants from CARs to use new access control features like continuous access evaluation (CAE).
Client access rules deprecation timeline
Client access rules deprecation timeline (Microsoft)

​”If you do not currently use CARs, cmdlets will be disabled for your tenant after October 2022,” the Exchange Team added.

“If you currently have CARs configured in your tenant you will be able to keep using them until September 2023, which provides you with time to migrate other, more resilient options.”

As Redmond explains, the switch to CAE access control to Exchange Online resources is designed to add extra resiliency by proactively terminating active user sessions and ensuring tenant policy change enforcement in almost real-time.

“Now with new features, like Continuous Access Evaluation (CAE) that allows Azure Active Directory applications to subscribe to critical events, that can then be evaluated and enforced in near real time; you can have better control while also adding resiliency to your organization,” the Exchange Team said.

Microsoft also recently warned customers that it would start disabling basic authentication in random tenants to improve Exchange Online security beginning October 1, 2022.

Article (https://www.bleepingcomputer.com/news/microsoft/microsoft-to-retire-exchange-online-client-access-rules-in-a-year/)

Roy Miehe | MspPortal Partners Inc. | Ceo/President
Security Software Distributor: Bitdefender , Barracuda, RackSpace, Axcient
“Where Service and Technical Skills Count”

By Sergiu Gatlan September 23, 2022 07:28 AM

Microsoft has acknowledged a known issue where copying files/shortcuts using Group Policy Preferences on Windows client devices might not work as expected after installing recent Windows cumulative updates released during this month’s Patch Tuesday.

On affected systems, files or shortcuts will not copy to the target drives or end up as zero-byte files when using Group Policy file operations.

“File copies using Group Policy Preferences might fail or might create empty shortcuts or files using 0 (zero) bytes,” Microsoft explained.

“Known affected Group Policy Objects are related to files and shortcuts in User Configuration -> Preferences -> Windows Settings in Group Policy Editor.”

The list of affected platforms includes client (from Windows 8.1 up to Windows 11 22H2) and server releases (from Windows Server 2008 SP2 and up to Windows Server 2022).

Microsoft acknowledged the issue following a stream of Windows admin reports across multiple social networks and on Microsoft’s online community regarding issues with Group Policy settings after deploying September 2022 Patch Tuesday updates.

At the time, some of the affected admins suggested a radical fix requiring manually uninstalling and hiding the offending cumulative updates. Unfortunately, this would also remove all fixes for recently patched security vulnerabilities.

However, multiple admins have also reported that un-checking the “Run in user security context” option on the affected GPOs will help address the file copying and shortcut creation problems.
Official workarounds are also available

Microsoft confirmed the last workaround shared by impacted customers before the issue was acknowledged, together with a couple of additional ways to mitigate the issue (any one of them is enough for mitigation) :

Uncheck the “Run in logged-on user’s security context (user policy option).” Note: This might not mitigate the issue for items using a wildcard (*).
Within the affected Group Policy, change “Action” from “Replace” to “Update.”
If a wildcard (*) is used in the location or destination, deleting the trailing “\” (backslash, without quotes) from the destination might allow the copy to be successful.

Redmond also added that its developers are working on a resolution for this known issue and will provide a fix with an upcoming update.

Article (https://www.bleepingcomputer.com/news/microsoft/microsoft-shares-workarounds-for-windows-group-policy-issues/)

Microsoft: Windows KB5017383 preview update added to WSUS by mistake
(https://www.bleepingcomputer.com/news/microsoft/microsoft-windows-kb5017383-preview-update-added-to-wsus-by-mistake/)
Microsoft rolls out emergency fix for blocked Windows logins (https://www.bleepingcomputer.com/news/microsoft/microsoft-rolls-out-emergency-fix-for-blocked-windows-logins/)

Roy Miehe | MspPortal Partners Inc. | Ceo/President
Security Software Distributor: Bitdefender , Barracuda, RackSpace, Axcient
“Where Service and Technical Skills Count”

By Sergiu Gatlan September 22, 2022 01:13 PM
Microsoft says a threat actor gained access to cloud tenants hosting Microsoft Exchange servers in credential stuffing attacks, with the end goal of deploying malicious OAuth applications and sending phishing emails.

“The investigation revealed that the threat actor launched credential stuffing attacks against high-risk accounts that didn’t have multi-factor authentication (MFA) enabled and leveraged the unsecured administrator accounts to gain initial access,” the Microsoft 365 Defender Research Team said.

“The unauthorized access to the cloud tenant enabled the actor to create a malicious OAuth application that added a malicious inbound connector in the email server.”

The attacker then used this inbound connector and transport rules designed to help evade detection to deliver phishing emails through the compromised Exchange servers.

The threat actors deleted the malicious inbound connector and all the transport rules between spam campaigns as an additional defense evasion measure.

In contrast, the OAuth application remained dormant for months between attacks until it was used again to add new connectors and rules before the next wave of attacks.

These email campaigns were triggered from Amazon SES and Mail Chimp email infrastructure commonly used to send marketing emails in bulk.
The attacker used a network of single-tenant applications as an identity platform throughout the attack.

After detecting the attack, Redmond took down all apps linked to this network, sent alerts, and recommended remediation measures to all affected customers.

Microsoft says this threat actor was linked to campaigns pushing phishing emails for many years.

The attacker was also seen sending high volumes of spam emails within short timeframes through other means “such as connecting to mail servers from rogue IP addresses or sending directly from legitimate cloud-based bulk email sending infrastructure.”

“The actor’s motive was to propagate deceptive sweepstakes spam emails designed to trick recipients into providing credit card details and signing up for recurring subscriptions under the guise of winning a valuable prize,” Microsoft further revealed.

“While the scheme possibly led to unwanted charges for targets, there was no evidence of overt security threats such as credential phishing or malware distribution.”

Article (https://www.bleepingcomputer.com/news/security/microsoft-exchange-servers-hacked-via-oauth-apps-for-phishing/)
Roy Miehe | MspPortal Partners Inc. | Ceo/President
Security Software Distributor: Bitdefender , Barracuda, RackSpace, Axcient
“Where Service and Technical Skills Count”