SecurityBrief Australia logo
Australia's leading source of cybersecurity and cyber-attack news
Partner content
Story image

A look at the MS Exchange zero-days and how to protect your business

By Sara Barker
Thu 29 Apr 2021
FYI, this story is more than a year old

When four zero-day vulnerabilities* within Microsoft Exchange were revealed in early March this year, the news came with a sense of urgency - the vulnerabilities were already being actively used and exploited by malicious threat actors in the wild.

The urgent message warned every organisation using Microsoft Exchange to patch their on-premise servers immediately and to scan their networks for signs of malicious activity.

The exploitations seen in the wild were first attributed to a nation state actor dubbed HAFNIUM, but the vulnerabilities and attacks have colloquially become known as “ProxyLogon” in reference to the main vulnerability of the zero-days involved.

Cybersecurity firm, Sophos, has published several alerts highlighting the threats DearCry and Black KingDom ransomware and a malicious Monero cryptominer actively exploiting the vulnerabilities.

A combination of these four vulnerabilities can lead to easy exploitation of your Exchange and according to Sophos Managed Threat Response senior director Matt Gangwer. 

“Given the broad installation of Exchange and its exposure to the internet, these vulnerabilities should not be taken lightly. Ensuring your organisation can identify and respond to the suspected vulnerabilities is crucial.”

“As a customer or partner using on-prem Exchange, the best course of action may be to assume that this has impacted your organisation.”

If they haven't already done so, organisations should follow these steps:

1. Patch or disable

Patch all on-premise Microsoft Exchange servers in your environment with the relevant security update. Details can be found on Microsoft’s Exchange Team blog.

If you are unable to patch, Microsoft provides a succinct mitigation tool (Exchange On-Premise Mitigation Tool) that’s available on GitHub via: https://msrc-blog.microsoft.com/2021/03/05/microsoft-exchange-server-vulnerabilities-mitigations-march-2021/ 

Sophos recommends you back up Exchange IIS/Server logs before patching and updating to maintain any forensic evidence that would indicate a successful exposure of your environment.

2. Determine possible exposure

Download and run the Test-ProxyLogon.ps1 script provided by Microsoft to determine possible exposure.

It is important to note that even with the patches installed, this will not address the presence of any malicious web shells. This is why the use of Microsoft’s script to identify affected servers and look for the presence of web shells is recommended.

Test-ProxyLogon.ps1 can output multiple .csv files per Exchange server, depending on what it finds. These .csv files can be viewed in a text editor or spreadsheet application.

The script will look for evidence of each vulnerability being abused, creating a .csv per CVE. It will also look for suspicious files (which may be web shells), which should be reviewed and calculate how many days back in the logs it can identify potential abuse of the vulnerabilities.

3. Look for web shells or other suspicious .aspx files

Many security products that provide protection for Microsoft server platforms (including the use of Exchange) can accurately identify the presence of these persistence mechanisms (web shells) and quarantine them and provide clear guidance on their removal. Deploy and scan your Exchange systems immediately.

4. Determine exposure and plan next steps

If you uncovered suspicious activity, plan your next steps, which could include acquiring help from a third-party forensics firm to do a deeper analysis or incident response.  

Conducting investigations in the wake of major incidents like this requires time and expertise. For many organisations, being able to be certain there is no adversarial activity in their network is simply out of the scope of their team’s capabilities.

For an expert team to watch over your network 24/7, identifying, investigating, and responding to threats that have evaded your defences, Sophos Managed Threat Response can help.

*The four vulnerabilities (CVEs) affecting Microsoft Exchange are:

  • CVE-2021-26855 
  • CVE-2021-26857 
  • CVE-2021-26858 
  • CVE-2021-27605
Related stories
Top stories
Story image
Phishing
MailGuard warns of new scam targeting Telstra customers
Telstra customers in Australia are being warned of a new scam involving "Unsuccessful Payment" messages.
Story image
Phishing
Vishing attacks reach all time high - Agari and PhishLabs
"Hybrid vishing campaigns continue to generate stunning numbers, representing 26.1% of total share in volume so far in 2022."
Story image
Cybersecurity
 Asia Pacific plagued by sophisticated bad bots - report
The three most common bot attacks were account takeover, content or price scraping, and scalping to obtain limited-availability items.
Story image
Data Protection
Information management capabilities to meet privacy requirements
Organisations with customers or operations across more than one country face a spate of new and proposed privacy and data protection laws.
Story image
Cybersecurity
BlackBerry offers Kaspersky replacement cybersecurity for the channel
BlackBerry advises that users of Kaspersky software in Australia and New Zealand undertake a rigorous risk analysis of their current security posture.
Story image
Training
Infosec unveils role-guided cybersecurity training roadmaps 
Infosec Skills Roles maps hands-on training and certifications to the 12 most in-demand cybersecurity roles to maximise training efficiency.
Story image
Artificial Intelligence
How to ensure ethical deployment of AI implementations
The increase in automation and machine technology such as AI and machine learning has unlocked a whole new level of scale and service to organisations. 
Story image
Cyber attacks
Devastating cyber attacks expected to hit energy sector
Energy executives anticipate life, property, and environment-compromising cyber attacks on the sector within the next two years.
Story image
Employment
Tech job moves - Forcepoint, Malwarebytes, SolarWinds & VMware
We round up all job appointments from May 13-20, 2022, in one place to keep you updated with the latest from across the tech industries.
Story image
Cloud Security
Aqua Security createa unified scanner for cloud native security
“By integrating more cloud native scanning targets into Trivy, such as Kubernetes, we are simplifying cloud native security."
Story image
Ransomware
APAC ranks third-highest region targeted by ransomware
Asia Pacific has ranked the third-highest region globally to be targeted by ransomware, according to cybersecurity firm Group-IB.
Story image
Surveillance
i-PRO releases smallest AI-based surveillance camera on the market
The new i-PRO mini network camera is now available, with a pocket-sized form factor and full AI analytics functionality.
Story image
Cybersecurity
Comcast to use ThreatQuotient for cybersecurity operations
Comcast, the parent company of NBC Universal and SKY Group, has chosen ThreatQ Platform and ThreatQ Investigations to meet their cybersecurity needs.
Story image
Ransomware
Employees on the frontline of cyber defense - report
In the first quarter of 2022, employees found themselves more than ever at the frontline of cyber defense, according to a new report from Kroll. 
Story image
Ponemon Institute
Email revealed to be riskiest channel for data loss
More than half (60%) of organisations experienced data loss or exfiltration caused by an employee mistake on email in the last 12 months.
Story image
Microsoft
Global cybersecurity insurance market worth $11.5b this year
Future Market Insights finds the cybersecurity insurance market is expected to reach USD$11.5 billion in 2022, growing to $61.2 billion in 10 years.
Story image
Artificial Intelligence
Gartner reveals top three tech trends for banks this year
Gartner says generative artificial intelligence, autonomic systems and privacy-enhancing computation are gaining traction in banking and investment services.
Story image
Managed service provider
Barracuda MSP Day 2022 highlights MSP opportunities
Barracuda Networks has released a report showing global services-related MSP revenue is set to increase by more than a third in 2022 compared to 2021.
Story image
Qualys
Qualys updates Cloud Platform solution with rapid remediation
The new update is designed to enable organisations to fix asset misconfigurations, patch OS and third-party applications, and deploy custom software.
Story image
Training
Trojan cyber attacks hitting SMBs harder than ever - Kaspersky
In 2022 the number of Trojan-PSW detections increased by almost a quarter compared to the same period in 2021 to reach 4,003,323.
Story image
Apricorn
Data backup plans inadequate, data still at risk - study
The Apricorn 2022 Global IT Security Survey revealed that while the majority organisations have data backup plans in place, data for many are at risk.
Story image
Nozomi Networks
Nozomi Networks, Siemens reveal software integration
Nozomi Networks and Siemens have extended their partnership by embedding Nozomi Networks’ software into the Siemens Scalance LPE local processing engine.
Story image
Cybersecurity
Cybersecurity prompts upgrade for 1.3 billion electricity meters
ABI Research finds Advanced Metering Infrastructure (AMI) and cybersecurity concerns are prompting the upgrade of 1.3 billion electricity meters by 2027.
Story image
Migration
Let’s clear the cloud visibility haze with app awareness
Increasingly, organisations are heading for the cloud, initiating new born-in-the-cloud architectures and migrating existing applications via ‘lift and shift’ or refactoring.
Story image
VPN
The most common online scams in Australia
No one is safe from online scammers, and many of these scammers have capitalised on the pandemic, using this confusing time to attack more people than ever.
Story image
Data Protection
Barracuda launches new capabilities for API Protection
"Every business needs this type of critical protection against API vulnerabilities and automated bot attacks," Barracuda says.
Story image
Cybersecurity
Infoblox's State of Security Report spotlights Australian remote work hazards
Attackers exploit weak WiFi, remote endpoints, and the cloud, costing 50% of organisations over $1.3 million in breach damages.
Story image
Silver Peak
The path to an adaptive, modern network
Managing and securing the network looks different than it did just two years ago—especially given that most of these networks are made up of multi-generations of infrastructure stitched together over time.
Story image
Ransomware
A third of companies paying ransom don’t recover data - report
Veeam's report finds 76% of businesses who are victims of cyberattacks paid the ransom to recover data, but a third were still unable to get their information back.
Story image
Malware
New vulnerabilities found in Nuspire’s Q1 2022 Threat Report
“Threat actors are quickly adjusting their tactics and these exploits tend to get industry attention, but the threat posed by older and attacks still persists."
Story image
Ransomware
Alarming surge in Conti Ransomware Group activity - report
A new report has identified a 7.6 per cent increase in the number of vulnerabilities tied to ransomware in Q1 2022.
Story image
SaaS
Rubrik Security Cloud marks 'next frontier' in cybersecurity
"The next frontier in cybersecurity pairs the investments in infrastructure security with data security giving companies security from the point of data."
Story image
Kubernetes
Sysdig unveils new Kubernetes troubleshooting and cloud innovations
Sysdig has introduced two new innovations that look to help bolster cloud services and simplify Kubernetes troubleshooting.
Story image
Sift
Sift shares crucial advice for preventing serious ATO breaches
Are you or your business struggling with Account Takeover Fraud (ATO)? One of the latest ebooks from Sift can provide readers with the tools and expertise to help launch them into the new era of account security.
Story image
ChildFund
ChildFund launches new campaign to protect children online
ChildFund says WEB Safe & Wise aims to protect children from sexual exploitation and abuse online while also empowering them to become digitally savvy. 
Story image
Cybersecurity
Noname Security partners with Netpoleon to target API issues
Specialist API security firm Noname Security has appointed Netpoleon as its distributor in Australia and New Zealand.
Story image
Remote Working
Australia’s remote workers face connectivity and security issues
SOTI's new report finds better video conferencing technology and improved security measures are top concerns for remote workers in Australia.
Story image
trust
9/10 Aussies to stop spending if personal data compromised
"Based on the patterns we are seeing among Australian consumers, it is evident that trust in a brand is exceptionally important."
Story image
Supply chain
Jetstack promotes better security with supply chain toolkit
The web-based resource is designed to help organisations evaluate and plan the crucial steps they need to establish effective software supply chain security.
Story image
Vectra AI
Understanding the weight on security leader’s shoulders, and how to shift it
Millions of dollars of government funding and internal budgets are being funnelled into cybersecurity to build resilience against sophisticated threats, indicating how serious this issue has become.
Story image
Amazon Web Services / AWS
RedShield leverages AWS to scale cybersecurity services
"Working with AWS gives RedShield the ability to mitigate significant application layer DDoS attacks, helping leaders adopt best practices and security architectures."
Story image
Remote Working
Successful digital transformation in the hybrid work era is about embracing shifting goalposts
As organisations embraced remote working, many discovered they lacked the infrastructure needed to support history’s first global load test of remote work capabilities.
Story image
Ransomware
APAC organisations fail to disclose ransomware breaches
85% of organisations in APAC were breached by ransomware at least once in the past five years, but only 28% publicly disclosed the incident.
Story image
New Relic
New Relic launches vulnerability management platform
New Relic has introduced New Relic Vulnerability Management to help organisations find and address security risks faster and with greater precision.