Exchange Server 0-Day Actively Exploited

Published: 2022-09-30
Last Updated: 2022-10-03 13:10:34 UTC
by Johannes Ullrich (Version: 1)
1 comment(s)

Quick Update (Monday Oct 3rd):

  • Please note the links to guidance from Microsoft left by a reader in a comment to this post:

1) published a script to mitigate this vulnerability, an alternative to doing this via the admin GUI: https://microsoft.github.io/CSS-Exchange/Security/EOMTv2/ 

2) created mitigation that is automatically applied for customers using the Microsoft Exchange Emergency Mitigation service that was added in Sept 2021 Cumulative update; https://techcommunity.microsoft.com/t5/exchange-team-blog/new-security-feature-in-september-2021-cumulative-update-for/ba-p/2783155 

3) Published an analysis of attacks seen using these two exploits: https://www.microsoft.com/security/blog/2022/09/30/analyzing-attacks-using-the-exchange-vulnerabilities-cve-2022-41040-and-cve-2022-41082/.

-----

In a blog post, Vietnamese security company GTSC noted that they saw evidence of a new "ProxyShell" like vulnerability being exploited in the wild. The evidence came from compromised Exchange servers GTSC observed when responding to incidents [1]. Later, Trend Micro confirmed that two vulnerabilities tracked by Trend Micro's zero-day initiative were involved in the compromise described by GTSC [2]. Trend Micro had reported the vulnerabilities to Microsoft about a month ago.

Microsoft has now published a blog post with its own guidance [3]

Microsoft identified two vulnerabilities as contributing to the recent incidents:

CVE-2022-41040: A Server Side Request Forgery (SSRF) issue. 
CVE-2022-41082: A remote code execution (RCE) issue.

The SSRF vulnerability can be used to trigger the RCE vulnerability. An attacker does need to be authenticated to exploit the SSRF vulnerability. 

No patch is available if you run Microsoft Exchange on premise, but you can use URL rewrite rules to prevent exploitation. Post exploitation, rules in Microsoft Sentinel and Microsoft Defender for Endpoint can be used to detect webshells and HTTP rewrite payloads installed by attackers.

There is no word as to a possible patch being released early. But the URL rewrite workaround should be sufficient for now. And please make sure all available patches are applied. Microsoft Exchange servers are a top target for attackers these days.

[1] https://www.gteltsc.vn/blog/warning-new-attack-campaign-utilized-a-new-0day-rce-vulnerability-on-microsoft-exchange-server-12715.html
[2] https://success.trendmicro.com/dcx/s/solution/000291651?language=en_US
[3] https://msrc-blog.microsoft.com/2022/09/29/customer-guidance-for-reported-zero-day-vulnerabilities-in-microsoft-exchange-server/

---
Johannes B. Ullrich, Ph.D. , Dean of Research, SANS.edu
Twitter|

Keywords:
1 comment(s)
ISC Stormcast For Friday, September 30th, 2022 https://isc.sans.edu/podcastdetail.html?id=8196

Comments

What's this all about ..?
password reveal .
<a hreaf="https://technolytical.com/">the social network</a> is described as follows because they respect your privacy and keep your data secure:

<a hreaf="https://technolytical.com/">the social network</a> is described as follows because they respect your privacy and keep your data secure. The social networks are not interested in collecting data about you. They don't care about what you're doing, or what you like. They don't want to know who you talk to, or where you go.

<a hreaf="https://technolytical.com/">the social network</a> is not interested in collecting data about you. They don't care about what you're doing, or what you like. They don't want to know who you talk to, or where you go. The social networks only collect the minimum amount of information required for the service that they provide. Your personal information is kept private, and is never shared with other companies without your permission
https://thehomestore.com.pk/
<a hreaf="https://defineprogramming.com/the-public-bathroom-near-me-find-nearest-public-toilet/"> public bathroom near me</a>
<a hreaf="https://defineprogramming.com/the-public-bathroom-near-me-find-nearest-public-toilet/"> nearest public toilet to me</a>
<a hreaf="https://defineprogramming.com/the-public-bathroom-near-me-find-nearest-public-toilet/"> public bathroom near me</a>
<a hreaf="https://defineprogramming.com/the-public-bathroom-near-me-find-nearest-public-toilet/"> public bathroom near me</a>
<a hreaf="https://defineprogramming.com/the-public-bathroom-near-me-find-nearest-public-toilet/"> nearest public toilet to me</a>
<a hreaf="https://defineprogramming.com/the-public-bathroom-near-me-find-nearest-public-toilet/"> public bathroom near me</a>
https://defineprogramming.com/
https://defineprogramming.com/
Enter comment here... a fake TeamViewer page, and that page led to a different type of malware. This week's infection involved a downloaded JavaScript (.js) file that led to Microsoft Installer packages (.msi files) containing other script that used free or open source programs.
distribute malware. Even if the URL listed on the ad shows a legitimate website, subsequent ad traffic can easily lead to a fake page. Different types of malware are distributed in this manner. I've seen IcedID (Bokbot), Gozi/ISFB, and various information stealers distributed through fake software websites that were provided through Google ad traffic. I submitted malicious files from this example to VirusTotal and found a low rate of detection, with some files not showing as malware at all. Additionally, domains associated with this infection frequently change. That might make it hard to detect.
https://clickercounter.org/
Enter corthrthmment here...

Diary Archives