logo_SVG-01
✕
  • Platform
    • Rewterz XDR
    • Rewterz Defense
    • Rewterz Threat Intelligence
    • Managed Security Services
    • Managed Penetration Testing
  • Services
    • Assess
      • Compromise Assessment
      • Advanced Persistent Threats Assessment
      • Penetration Testing
      • Secure Architecture Design & Review
      • Red Team Assessment
      • Purple Team Assessment
      • Social Engineering
      • Source Code Review
    • Transform
      • SOC Consultancy
      • SOC Maturity Assessment
      • SOC Model Evaluation
      • SOC Gap Analysis
      • SIEM Gap Analysis
      • SIEM Optimization
      • SOC Content Pack
    • Train
      • Simulated Cyber Attack Exercise
      • Tabletop Exercise
      • Security Awareness and Training
    • Respond
      • Incident Analysis
      • Incident Response
  • Solutions
  • Resources
    • Blogs
    • Press Releases
    • Threat Insights
      • Threat Intelligence Reports
      • Threat Advisories
      • Monthly Threat Insights
  • Why Rewterz?
    • About Us
    • Careers
    • Contact
logo_SVG-01
  • Platform
    xdrLogo
    center_new
    Read More about XDR

    Platform

    • Rewterz XDR
    • Rewterz Defense
    • Rewterz Threat Intelligence
    Rewterz Threat Alert – Private Information on Google Calendars Publicly Exposed and Exploited

    Managed Security Services

    • Managed Security Monitoring
    • Remote SOC
    • Onsite SOC
    • Hybrid SOC

    Managed Penetration Testing

    Rewterz penetration testing services help organizations determine if a cyber attacker can gain access to their critical assets while giving them detailed insights of the overall business impact of a cyber attack.

  • Services

    Assess

    • Compromise Assessment
    • APT Assessment
    • Penetration Testing
    • Architecture Design & Review
    • Red Team Assessment
    • Purple Team Assessment
    • Social Engineering
    • Source Code Review

    Transform

    • SOC Consultancy
    • SOC Maturity Assessment
    • SOC Model Evaluation
    • SOC Gap Analysis
    • SIEM Gap Analysis
    • SIEM Optimization
    • SOC Content Pack

    Train

    • Simulated Cyber Attack Exercise
    • Tabletop Exercise
    • Security Awareness and Training

    Respond

    • Incident Analysis
    • Incident Response
  • Solutions
  • Resources

    Resources

    • Blog
    • Press Releases
    March 25, 2023
    March 25, 2023
    Rewterz Threat Alert – GandCrab or .CRAB Ransomware – Active IOCs
    Severity Medium Analysis Summary GandCrab – a ransomware-as-a-service variant – was discovered in early 2018. At least five versions of GandCrab have been created since its […]
    March 25, 2023
    March 25, 2023
    Rewterz Threat Alert – NJRAT – Active IOCs
    Severity Medium Analysis Summary NjRat is a Remote Access Trojan, which is found leveraging Pastebin to deliver a second-stage payload after initial infection. There are multiple […]
    March 24, 2023
    March 24, 2023
    Rewterz Threat Advisory – CVE-2023-20113 – Cisco SD-WAN vManage Software Vulnerability
    Severity Medium Analysis Summary CVE-2023-20113  Cisco SD-WAN vManage Software is vulnerable to cross-site request forgery, caused by improper validation of user-supplied input. By persuading an authenticated […]

    Threat Insights

    16
    pdf-file (1)
    Annual Threat Intelligence Report 2022
    • Threat Advisories
    • Monthly Threat Insights
    • Threat Intelligence Reports
  • Why Rewterz?

    About Us

    Before Rewterz got its start, the market was in dire need of a specialized and dedicated information security company. It was nearly impossible for businesses to find a trustworthy provider that could truly cover all of their bases. We wanted to meet this need, giving companies across the globe a chance to get ahead while knowing that their data is in good hands.

    Read More

    play_btn_Smallplay_btn_hover_Small
    leadership

    Our Leadership

    Our leadership team brings together years of knowledge and experience in cybersecurity to drive our company's mission and vision. Our team is passionate about delivering high-quality products and services, leading by example and assisting our clients in securing their organization’s environment.
    help

    CSR

    At Rewterz, we believe that businesses have a responsibility to impact positively and contribute to the well-being of our communities as well as the planet. That's why we are committed to operating in a socially responsible and sustainable way.

    Connect with Us

    • Contact
    • Careers
Get in Touch
logo_SVG-01
  • Platform
    xdrLogo
    center_new
    Read More about XDR

    Platform

    • Rewterz XDR
    • Rewterz Defense
    • Rewterz Threat Intelligence
    Rewterz Threat Alert – Private Information on Google Calendars Publicly Exposed and Exploited

    Managed Security Services

    • Managed Security Monitoring
    • Remote SOC
    • Onsite SOC
    • Hybrid SOC

    Managed Penetration Testing

    Rewterz penetration testing services help organizations determine if a cyber attacker can gain access to their critical assets while giving them detailed insights of the overall business impact of a cyber attack.

  • Services

    Assess

    • Compromise Assessment
    • APT Assessment
    • Penetration Testing
    • Architecture Design & Review
    • Red Team Assessment
    • Purple Team Assessment
    • Social Engineering
    • Source Code Review

    Transform

    • SOC Consultancy
    • SOC Maturity Assessment
    • SOC Model Evaluation
    • SOC Gap Analysis
    • SIEM Gap Analysis
    • SIEM Optimization
    • SOC Content Pack

    Train

    • Simulated Cyber Attack Exercise
    • Tabletop Exercise
    • Security Awareness and Training

    Respond

    • Incident Analysis
    • Incident Response
  • Solutions
  • Resources

    Resources

    • Blog
    • Press Releases
    March 25, 2023
    March 25, 2023
    Rewterz Threat Alert – GandCrab or .CRAB Ransomware – Active IOCs
    Severity Medium Analysis Summary GandCrab – a ransomware-as-a-service variant – was discovered in early 2018. At least five versions of GandCrab have been created since its […]
    March 25, 2023
    March 25, 2023
    Rewterz Threat Alert – NJRAT – Active IOCs
    Severity Medium Analysis Summary NjRat is a Remote Access Trojan, which is found leveraging Pastebin to deliver a second-stage payload after initial infection. There are multiple […]
    March 24, 2023
    March 24, 2023
    Rewterz Threat Advisory – CVE-2023-20113 – Cisco SD-WAN vManage Software Vulnerability
    Severity Medium Analysis Summary CVE-2023-20113  Cisco SD-WAN vManage Software is vulnerable to cross-site request forgery, caused by improper validation of user-supplied input. By persuading an authenticated […]

    Threat Insights

    16
    pdf-file (1)
    Annual Threat Intelligence Report 2022
    • Threat Advisories
    • Monthly Threat Insights
    • Threat Intelligence Reports
  • Why Rewterz?

    About Us

    Before Rewterz got its start, the market was in dire need of a specialized and dedicated information security company. It was nearly impossible for businesses to find a trustworthy provider that could truly cover all of their bases. We wanted to meet this need, giving companies across the globe a chance to get ahead while knowing that their data is in good hands.

    Read More

    play_btn_Smallplay_btn_hover_Small
    leadership

    Our Leadership

    Our leadership team brings together years of knowledge and experience in cybersecurity to drive our company's mission and vision. Our team is passionate about delivering high-quality products and services, leading by example and assisting our clients in securing their organization’s environment.
    help

    CSR

    At Rewterz, we believe that businesses have a responsibility to impact positively and contribute to the well-being of our communities as well as the planet. That's why we are committed to operating in a socially responsible and sustainable way.

    Connect with Us

    • Contact
    • Careers
Get in Touch
Rewterz
Rewterz Threat Advisory – CVE-2019-12922 – phpMyAdmin Cross Site Request Forgery Vulnerability
September 18, 2019
Rewterz
Rewterz Threat Alert – Formbook Malware Continues to target Victims via Phishing Emails
September 18, 2019

Rewterz Threat Alert – Private Information on Google Calendars Publicly Exposed and Exploited

September 18, 2019

Severity

High

Analysis Summary

Over 8000 Google Calendars are found to be publicly accessible using Google search engine. It not only allows public to access sensitive information saved to the calendars but also enables them to add new events with maliciously crafted information or links. The act of making the calendar public is a handy feature intended to facilitate collaboration, and requires user interaction in the form of following warning pop up:

image-1568803848.jpg

Many people set the setting to public, intended or unintended, in order to share these events with other people. However, the public setting does not require people to have a hyperlink of the calendar in order to access it. They can view and edit anything on it just by a single search query. Public calendars of various organizations exposed sensitive information including email ids, their event names, event details, location, meeting links, zoom meeting links, google hangout links, internal presentation links and much more, as shown below.

image-1568804246.jpg

image-1568804250.jpg

Moreover, Google neither notifies the creator of a public Calendar when someone accesses/adds an event to it nor sends any reminders that the calendar is publicly accessible, making it exploitable by phishers.

Researchers reported that many of the exposed calendars belonged to top 500 Alexa company’s employees.

Exploitation of Google Calendar Service in Cyber Incidents

Apparently helpful in collaboration, this feature of Google Calendar Service is being exploited to target users with credential-stealing attacks, in which phishers send victims an email containing a crafted event invitation with malicious links.

Since anyone can now edit one of these calendars to send you invitations to events or meetings, threat actors are now sending such malicious invitations en masse without raising concerns. The spam details may claim that you are entitled to a cash payment for some reason, and a link will be provided to let you receive the amount. The malicious link will redirect to spam pages demanding your credit card details either for the transfer of your payment, or for you to pay some registration fee before claiming your reward.

Not just credential theft, this service can also be exploited for delivering malware and ransomware on target systems, clicking which the targets will fall victim to the attack.

Impact

  • Information Disclosure
  • Credential Theft
  • Potential Financial Loss

Remediation

  • Check privacy settings of your Google calendars and make them private.
  • To share a calendar with someone privately, invite specific users by adding their email addresses under Calendar settings.
  • Do not click on links provided with Google Calendar invitations before verifying from the sender.

Platform

  • Rewterz XDR
  • Rewterz Defense
  • Rewterz Threat Intelligence

Managed Security Services

  • Managed Security Monitoring
  • Remote SOC
  • Onsite SOC
  • Hybrid SOC

Assess

  • Compromise Assessment
  • APT Assessment
  • Penetration Testing
  • Architecture Design & Review
  • Red Team Assessment
  • Purple Team Assessment
  • Social Engineering
  • Source Code Review

Transform

  • SOC Consultancy
  • SOC Maturity Assessment
  • SOC Model Evaluation
  • SOC Gap Analysis
  • SIEM Gap Analysis
  • SIEM Optimization
  • SOC Content Pack

Train

  • Simulated Cyber Attack Exercise
  • Tabletop Exercise
  • Security Awareness and Training

Respond

  • Incident Analysis
  • Incident Response

Threat Insights

  • Threat Advisories
  • Monthly Threat Insights
  • Threat Intelligence Reports

Resources

  • Blog
  • Press Releases

Connect With Us

  • Contact
  • Careers
COPYRIGHT © REWTERZ. ALL RIGHTS RESERVED.
Get a Demo