閉める
閉める
明日に向けたネットワーク
明日に向けたネットワーク
サポートするアプリケーションとユーザー向けに設計された、より高速で、より安全で、回復力のあるネットワークへの道を計画します。
          Netskopeを体験しませんか?
          Get Hands-on With the Netskope Platform
          Here's your chance to experience the Netskope One single-cloud platform first-hand. Sign up for self-paced, hands-on labs, join us for monthly live product demos, take a free test drive of Netskope Private Access, or join us for a live, instructor-led workshops.
            SSEのリーダー。 現在、シングルベンダーSASEのリーダーです。
            SSEのリーダー。 現在、シングルベンダーSASEのリーダーです。
            Netskope、2024年Gartner®社のシングルベンダーSASEのマジック・クアドラントでリーダーの1社の位置付けと評価された理由をご確認ください。
              ダミーのためのジェネレーティブAIの保護
              ダミーのためのジェネレーティブAIの保護
              Learn how your organization can balance the innovative potential of generative AI with robust data security practices.
                Modern data loss prevention (DLP) for Dummies eBook
                最新の情報漏えい対策(DLP)for Dummies
                Get tips and tricks for transitioning to a cloud-delivered DLP.
                  SASEダミーのための最新のSD-WAN ブック
                  Modern SD-WAN for SASE Dummies
                  遊ぶのをやめる ネットワークアーキテクチャに追いつく
                    リスクがどこにあるかを理解する
                    Advanced Analytics transforms the way security operations teams apply data-driven insights to implement better policies. With Advanced Analytics, you can identify trends, zero in on areas of concern and use the data to take action.
                        レガシーVPNを完全に置き換えるための6つの最も説得力のあるユースケース
                        レガシーVPNを完全に置き換えるための6つの最も説得力のあるユースケース
                        Netskope One Private Access is the only solution that allows you to retire your VPN for good.
                          Colgate-Palmoliveは、スマートで適応性のあるデータ保護により「知的財産」を保護します
                          Colgate-Palmoliveは、スマートで適応性のあるデータ保護により「知的財産」を保護します
                            Netskope GovCloud
                            NetskopeがFedRAMPの高認証を達成
                            政府機関の変革を加速するには、Netskope GovCloud を選択してください。
                              Let's Do Great Things Together
                              Netskopeのパートナー中心の市場開拓戦略により、パートナーは企業のセキュリティを変革しながら、成長と収益性を最大化できます。
                                Netskopeソリューション
                                Netskope Cloud Exchange
                                Netskope Cloud Exchange (CE) provides customers with powerful integration tools to leverage investments across their security posture.
                                  Netskopeテクニカルサポート
                                  Netskopeテクニカルサポート
                                  クラウドセキュリティ、ネットワーキング、仮想化、コンテンツ配信、ソフトウェア開発など、多様なバックグラウンドを持つ全世界にいる有資格のサポートエンジニアが、タイムリーで質の高い技術支援を行っています。
                                    Netskopeの動画
                                    Netskopeトレーニング
                                    Netskopeのトレーニングは、クラウドセキュリティのエキスパートになるためのステップアップに活用できます。Netskopeは、お客様のデジタルトランスフォーメーションの取り組みにおける安全確保、そしてクラウド、Web、プライベートアプリケーションを最大限に活用するためのお手伝いをいたします。

                                      Leaky Helpdesk – Accidental Exposure of Zendesk Attachments

                                      Jul 22 2020

                                      Does your helpdesk publicly expose the files you upload to it? Is there malware lurking in your helpdesk? In this latest edition of our leaky cloud app series, we uncover publicly accessible data in the Zendesk instances belonging to more than 350 organizations. This exposed data includes confidential information, malware, and even some COVID-19 themed Trojans. This blog post quantifies the scope of the problem and identifies steps you can take to lock down your Zendesk instance and prevent unwanted exposure. 

                                      This is the fourth installation of our leaky cloud app series, in which we highlight the many different ways cloud data leaks occur and provide guidance to avoid them. Our earlier posts covered Google Calendar, Google Groups, and Google Link Sharing

                                      Zendesk attachments

                                      By default, Zendesk attachments are accessible to anyone who has the link requiring no authentication. This is the root cause of the exposures we have discovered.

                                      Zendesk attachment links are in the format – http://<instance>.zendesk.com/attachments/token/<token_id>/?name<file_name>

                                      • instance – Name of the instance
                                      • token_id – Token for the attachment (generally with the length of 25 characters (a-z0-9))
                                      • file_name – Name of the file

                                      The shared attachment links by default can be accessed by anyone who has the link without any authentication. Though this won’t make the data indexable by search engines, it can likely pose exposure concerns in the following ways:

                                      • If a link is leaked, it can be accessed by anyone regardless of whether they are part of your organization.
                                      • Users can access the links even after leaving the organization.

                                      Among the different types of data we discovered via leaked links from more than 350 organization were: 

                                      • Employee resumes
                                      • Travel itineraries and documents
                                      • Bank and financial statements
                                      • Product installation guides
                                      • Emails
                                      • Invoices and purchase orders
                                      • Customer contact details
                                      • Medical documents
                                      • Social security numbers, driver’s license numbers, and bank account numbers
                                      • Product features and roadmaps
                                      • Passwords
                                      • Logfiles and screenshots
                                      • License keys
                                      • Meeting links
                                      • Drivers licenses and passports

                                      The instances that exposed the data belonged to private, public, and government organizations working in the following industries:

                                      • Retail and e-commerce
                                      • Hospitals and medical firms
                                      • Travel agencies
                                      • Educational institutions
                                      • Consultancies

                                      Zendesk spreading malware

                                      Any cloud service that provides file hosting via public, unauthenticated links can potentially be used to spread malware. In this section, we describe one such instance we uncovered of publicly accessible malware hosted in Zendesk. We have previously blogged about other apps being used as an attack vector in the same way, including a Salesforce Pardot CRM attack.

                                      Support portals typically have lots of people outside the organization creating tickets and uploading attachments. This increases the possibility of a compromised device, compromised account, or malicious user attaching malware to a ticket.

                                      This is problematic in two regards. First, the tickets and attachments are likely to be widely shared within the target organization, and therefore can also be used to spread malware within the organization. Second, if the attachments are public, the link to the malware can be used to target victims anywhere on the Internet. Hosting malware in cloud applications is a common tactic used to avoid detection by products that rely solely on URL reputation. 

                                      Malicious Excel spreadsheet 

                                      One of the publicly shared malware threats we found in Zendesk belonged to a large retailer in the United States and contained a COVID-19 lure: a malicious Excel file named  covid19_<masked>.xls.  The threat actor embedded a malicious Excel 4 macro formula in one of the 16 hidden sheets. Excel macros were used instead of the VBA macros commonly used in malicious Excel files, as they are both less likely to be detected by scanning engines and more likely to be enabled in the editor.

                                      The Excel 4 macro formulas are invoked in the workbook by using the “Auto_Open” option to download the next stage payload from toliku[.]com. At the time of analysis, the URL was down and not serving any payload, but was previously serving the Dridex malware.

                                      Figure 1 shows how to view the sheet ‘QMBVLCQaJJviKgsHo’ which contains the malicious URL.

                                      Figure showing URL hidden as an Excel 4 macros formula in a hidden sheet.
                                      Figure 1: URL hidden as an Excel 4 macros formula in a hidden sheet

                                      Disclosure

                                      Netskope reported the exposures we uncovered to the affected organizations in July 2020.

                                      Conclusion

                                      This edition of our leaky cloud apps series provided a detailed synopsis of how confidential information gets leaked through misconfigured Zendesk attachment links. We also detailed how malware can spread using Zendesk. We recommend turning on the “Require authentication to download” option to avoid accidental exposure as shown in Figure 2.

                                      Figure 2: Default option for attachments in Zendesk

                                      After enabling this option, private linked attachments with the shared file links will now require authentication.

                                      author image
                                      Ashwin Vamshi
                                      Ashwin Vamshi is a Security Researcher with innate interest in targeted attacks and malwares using cloud services.
                                      Ashwin Vamshi is a Security Researcher with innate interest in targeted attacks and malwares using cloud services.

                                      Stay informed!

                                      Subscribe for the latest from the Netskope Blog