Netskope named a Leader in the 2022 Gartner® Magic Quadrant™ for Security Service Edge. Get the Report.

  • Security Service Edge Products

    Protect against advanced and cloud-enabled threats and safeguard data across all vectors.

  • Borderless SD-WAN

    Confidently provide secure, high-performance access to every remote user, device, site, and cloud.

  • Platform

    Unrivaled visibility and real-time data and threat protection on the world's largest security private cloud.

Netskope Named a Leader in the 2022 Gartner Magic Quadrant™ for SSE Report

Get the report Go to Products Overview
Netskope gartner mq 2022 sse leader

Gartner® Quick Answer: How Does Netskope’s Acquisition of Infiot Impact SD-WAN, SASE, and SSE Projects?

Get the report
Quick Answer: How Does Netskope’s Acquisition of Infiot Impact SD-WAN, SASE and SSE Projects?

Netskope delivers a modern cloud security stack, with unified capabilities for data and threat protection, plus secure private access.

Explore our platform
Birds eye view metropolitan city

Make the move to market-leading cloud security services with minimal latency and high reliability.

Learn more
Lighted highway through mountainside switchbacks

Prevent threats that often evade other security solutions using a single-pass SSE framework.

Learn more
Lighting storm over metropolitan area

Zero trust solutions for SSE and SASE deployments

Learn more
Boat driving through open sea

Netskope enables a safe, cloud-smart, and fast journey to adopt cloud services, apps, and public cloud infrastructure.

Learn more
Wind turbines along cliffside
  • Our Customers

    Netskope serves more than 2,000 customers worldwide including more than 25 of the Fortune 100

  • Customer Solutions

    We are here for you and with you every step of the way, ensuring your success with Netskope.

  • Training and Certification

    Netskope training will help you become a cloud security expert.

We help our customers to be Ready for Anything

See our Customers
Woman smiling with glasses looking out window

Netskope’s talented and experienced Professional Services team provides a prescriptive approach to your successful implementation.

Learn more
Netskope Professional Services

Secure your digital transformation journey and make the most of your cloud, web, and private applications with Netskope training.

Learn more
Group of young professionals working
  • Resources

    Learn more about how Netskope can help you secure your journey to the cloud.

  • Blog

    Learn how Netskope enables security and networking transformation through security service edge (SSE).

  • Events & Workshops

    Stay ahead of the latest security trends and connect with your peers.

  • Security Defined

    Everything you need to know in our cybersecurity encyclopedia.

Security Visionaries Podcast

Episode 18: Fostering Relationships for Security Awareness

Play the podcast
Black man sitting in conference meeting

Read the latest on how Netskope can enable the Zero Trust and SASE journey through security service edge (SSE) capabilities.

Read the blog
Sunrise and cloudy sky


Netskope is positioned to help you begin your journey and discover where Security, Networking, and Zero Trust fit in the SASE world.

Learn more

What is Security Service Edge?

Explore the security side of SASE, the future of network and protection in the cloud.

Learn more
Four-way roundabout
  • Company

    We help you stay ahead of cloud, data, and network security challenges.

  • Why Netskope

    Cloud transformation and work from anywhere have changed how security needs to work.

  • Leadership

    Our leadership team is fiercely committed to doing everything it takes to make our customers successful.

  • Partners

    We partner with security leaders to help you secure your journey to the cloud.

Netskope enables the future of work.

Find out more
Curvy road through wooded area

Netskope is redefining cloud, data, and network security to help organizations apply Zero Trust principles to protect data.

Learn more
Switchback road atop a cliffside

Thinkers, builders, dreamers, innovators. Together, we deliver cutting-edge cloud security solutions to help our customers protect their data and people.

Meet our team
Group of hikers scaling a snowy mountain

Netskope’s partner-centric go-to-market strategy enables our partners to maximize their growth and profitability while transforming enterprise security.

Learn more
Group of diverse young professionals smiling

Phishing in the public cloud: You’ve been served

Oct 03 2018
microsoft azure
Microsoft Azure Security
Netskope Threat Research Labs
pdf decoy
Vulnerability Advisory

Netskope Threat Protection recently detected an interesting PDF decoy hosted in Google Drive. The PDF decoy was impersonating a law firm in Denver, CO. The PDF decoy linked to an Office 365 phishing page hosted in Azure blob storage. As the phishing bait is hosted in Azure blob storage, it has a Microsoft-issued domain and SSL certificate. The combination of the Microsoft domain, certificate, and content make this bait particularly convincing and difficult to recognize as phishing. In this post, we provide detailed analyses of the PDF decoy and phishing site. Along the way, we identify similar phishing sites hosted in Azure blob storage. We conclude with some recommendations to help protect you and your organization from falling victim to similar phishing campaigns.

Netskope Detections

Netskope Threat Protection detects the PDF decoys described in this post as PDF_PHISH.Gen1


The phishing sites we discovered were reported to Microsoft on 17 September 2018.


The PDF decoys traditionally arrive as email attachments to victims. They are crafted to contain legitimate content and come from legitimate sources. Often, attachments are saved to cloud storage services, like Google Drive. Sharing these documents with other users can result in the occurrence of a secondary propagation vector like the CloudPhishing Fan-out Effect. In this case, the document originally arrived in an email and was saved to Google Drive, where Netskope Advanced Threat Protection detected the file and prevented potential credential loss or fan-out.  

Analysis of the PDF decoy

The PDF decoy impersonates a law practice based out of Denver and was named “Scanned Document… Please Review.pdf”. The PDF contains a link to download the actual PDF, shown in Figure 1.

Figure 1: Message displayed on execution of the PDF

Upon clicking the “Download PDF” hyperlink, the victim is presented with a message that the document is trying to connect to an Azure blob storage URL https://onedriveunbound80343[.] as shown in Figure 2.

Figure 2: PDF decoy connecting to https://onedriveunbound80343[.]

The phishing web page presented to the victim after clicking the hyperlink is shown in Figure 3.

Figure 3: Phishing web page displayed to the victim

This phishing webpage is hosted in Azure blob storage. As a result, it has a valid Microsoft-issued SSL certificate and is hosted on a Microsoft-owned domain, as shown in Figure 4.

Figure 4: Phishing webpage hosted in Azure blob storage

At face value, seeing a Microsoft domain and a Microsoft-issued SSL certificate, on a site asking for Office 365 credentials is pretty strong evidence that the site is legitimate, and are likely enough to convince a user to enter their credentials. Upon clicking continue, the victim’s credentials are uploaded to https://searchurl[.]bid/livelogins2017/finish40.php as shown in Figure 5.

Figure 5: Victims credentials uploaded to https://searchurl[.]bid/livelogins2017/finish4.php

The victim is then directed to another phishing page hosted in blob storage https://onedriveunbound80343[.] through the referer https://searchurl[.]bid/livelogins2017/finish40.php.

Figure 6: Redirection to another phishing page

The phishing page displays a message that the email or password is invalid. This message displayed is not a result of validating the credentials, but instead hard-coded as shown in Figure 7.

Figure 7: Phished page displays a message that the email or password is invalid

Upon entering the details again, the victim’s credentials are again sent to https://searchurl[.]bid/livelogins2017/finish4.php as shown in Figure 8.

Figure 8: Victims credentials uploaded to https://searchurl[.]bid/livelogins2017/finish4.php

The victim is then shown a series of redirects to several landing pages posing to download the secured document as shown in Figure 9.

Figure 9: Series of pages displayed after entering the credentials

After all these pages are displayed, the victim is finally redirected to a Microsoft page,, but no document is downloaded to the victim’s machine. As the document is not downloaded, the victim might again try to re-validate the credentials or enter credentials related to another account.

Existence of similar strains

The PDF decoy we analyzed contained metadata like CreatorTool, Creator, and Producer as shown in Figure 10 that we used to identify similar attacks.

Figure 10: Decoy PDF metadata.

We found two more PDF decoys containing the same metadata. These included links to another phishing page hosted in blob storage, https://onedriveassumably232[.] These PDFs impersonated an Oregon-based dental equipment manufacturer, as shown in Figure 11.

Figure 11: PDF decoy connecting to https://onedriveassumably232[.]

Similar to the original bait, the credentials were sent to the same domain with a different URL path, i.e., https://searchurl[.]bid/livelogins2017/finish35.php. At the time of analysis, searchurl[.]bid resolved to the IP 181.215.136[.]146. The website is powered by Vesta, an open source hosting control panel and registered to Digital Energy Technologies Chile SpA, CL. Virustotal passive DNS also showed that the IP resolved to domains as shown in Figure 12.

Figure 12: Domains resolved by 212.83.167[.]116 in VirusTotal

Based on the URLs hosted in searchurl[.]bid and the resolved IP, there is evidence this operation has been going since August 2018. The passive DNS results also contained several iterations and combinations of domains and URL paths used by the threat actor. We don’t have any evidence to believe that the phishing campaigns are deliberately targeting the companies they were impersonating. Instead, the only link we found was that small companies in the U.S. were chosen. This attack appears to be broadly targeted toward O365 users in the US.

Other than use of Azure blob storage, another attribute of this phishing campaign that differentiates it from others we have seen in the past is its SSL usage. Every resource that is part of this campaign, including the baits in Azure and the PHP scripts for actually collecting the credentials are served over HTTPS.  The searchurl[.]bid domain has a valid SSL cert issued by LetsEncrypt. Most campaigns we have seen do not use SSL so prevalently. Using valid SSL certificates is a tool used by the threat actor to craft a more convincing bait. It is evidence that attackers are having to increase the realism of their campaigns to reach their intended targets.


We have discovered a phishing attack using themed PDF decoys and Azure blob storage to steal Office 365 credentials. This phishing campaign is noteworthy because it was designed to trick users that are savvy enough to check that the domain and SSL certificate of a website match its content. In this case, the phishing bait was a Microsoft Office 365 login page, hosted on a Microsoft domain, with a valid Microsoft-issued certificate. Users can recognize that this is a phishing site based on the subdomain, which indicates that it is in Azure blob storage, and not an official Microsoft website. Enterprises should educate their users to recognize AWS, Azure, and GCP object store URLs, so they can discern phishing sites from official sites. Netskope can also prevent similar phishing campaigns from spreading in your cloud environments. Netskope has reported the phishing sites hosted in Azure blob to the Microsoft Security Response Center. We will continue to closely monitor the developments of the PDF decoys using cloud storage services, Platform as a Service (PaaS) and Infrastructure as a Service (IaaS) and update our findings with more interesting developments.


Netskope recommends the following recommendations to combat cloud-based phishing campaigns:

  • Always check the domain of the link. Know the domains typically used when you login to sensitive services. Additionally, be able to identify common object store domains, such as those used by Azure blob storage. This knowledge will help you differentiate between well-crafted phishing sites and official sites.
  • Deploy a real-time visibility and control solution to monitor activities across sanctioned and unsanctioned cloud accounts.
  • Get comprehensive threat and malware detection for IaaS, SaaS, PaaS, and the web with real-time, multi-layered threat detection and remediation to prevent your organization from unknowingly spreading similar threats. Under the shared responsibility model, you are responsible for securing the data in your applications and preventing the spread of malware.
  • Keep systems and antivirus updated with the latest releases and patches.
author image
Ashwin Vamshi
Ashwin Vamshi is a Security Researcher with innate interest in targeted attacks and malwares using cloud services. He is primarily focusing in identifying new attack vectors and malwares, campaigns and threat actors using ‘cloud as an attack vector.’