• Home
  • Cyber Crime
  • Cyber warfare
  • APT
  • Data Breach
  • Deep Web
  • Digital ID
  • Hacking
  • Hacktivism
  • Intelligence
  • Internet of Things
  • Laws and regulations
  • Malware
  • Mobile
  • Reports
  • Security
  • Social Networks
  • Terrorism
  • ICS-SCADA
  • POLICIES
  • Contact me
MUST READ

Athlete or Hacker? Russian basketball player accused in U.S. ransomware case

 | 

U.S. CISA adds Citrix NetScaler ADC and Gateway flaw to its Known Exploited Vulnerabilities catalog

 | 

UK NCA arrested four people over M&S, Co-op cyberattacks

 | 

PerfektBlue Bluetooth attack allows hacking infotainment systems of Mercedes, Volkswagen, and Skoda

 | 

Qantas data breach impacted 5.7 million individuals

 | 

DoNot APT is expanding scope targeting European foreign ministries

 | 

Nippon Steel Solutions suffered a data breach following a zero-day attack

 | 

Iranian group Pay2Key.I2P ramps Up ransomware attacks against Israel and US with incentives for affiliates

 | 

Hackers weaponize Shellter red teaming tool to spread infostealers

 | 

Microsoft Patch Tuesday security updates for July 2025 fixed a zero-day

 | 

Italian police arrested a Chinese national suspected of cyberespionage on a U.S. warrant

 | 

U.S. CISA adds MRLG, PHPMailer, Rails Ruby on Rails, and Synacor Zimbra Collaboration Suite flaws to its Known Exploited Vulnerabilities catalog

 | 

IT Worker arrested for selling access in $100M PIX cyber heist

 | 

New Batavia spyware targets Russian industrial enterprises

 | 

Taiwan flags security risks in popular Chinese apps after official probe

 | 

U.S. CISA adds Google Chromium V8 flaw to its Known Exploited Vulnerabilities catalog

 | 

Hunters International ransomware gang shuts down and offers free decryption keys to all victims

 | 

SECURITY AFFAIRS MALWARE NEWSLETTER ROUND 52

 | 

Security Affairs newsletter Round 531 by Pierluigi Paganini – INTERNATIONAL EDITION

 | 

North Korea-linked threat actors spread macOS NimDoor malware via fake Zoom updates

 | 
  • Home
  • Cyber Crime
  • Cyber warfare
  • APT
  • Data Breach
  • Deep Web
  • Digital ID
  • Hacking
  • Hacktivism
  • Intelligence
  • Internet of Things
  • Laws and regulations
  • Malware
  • Mobile
  • Reports
  • Security
  • Social Networks
  • Terrorism
  • ICS-SCADA
  • POLICIES
  • Contact me
  • Home
  • Breaking News
  • Hacking
  • Flaws in Zimbra could allow to takeover webmail server of a targeted organization

Flaws in Zimbra could allow to takeover webmail server of a targeted organization

Pierluigi Paganini July 27, 2021

Researchers discovered flaws in Zimbra email collaboration software that could allow attackers to compromise email accounts by sending a malicious email.

Cybersecurity researchers have discovered multiple security vulnerabilities, tracked as CVE-2021-35208 and CVE-2021-35208, in Zimbra email collaboration software.

An unauthenticated attacker could chain these vulnerabilities to fully takeover a Zimbra webmail server of a targeted organization. An attacker could trigger the flaws to potentially compromise email accounts by sending a malicious message. The vulnerabilities were discovered by SonarSource vulnerability researcher, Simon Scannell.

The impact of the flaws could be severe because Zimbra is used by over 200,000 businesses and over a thousand government & financial institutions. 

The CVE-2021-35208 flaw is stored XSS issue that resides in the ZmMailMsgView.js of the Calendar Invite component in Zimbra Collaboration Suite 8.8.x before 8.8.15 Patch 23, it was rated with a CVSS score of 5.4.

“The first vulnerability is a Cross-Site Scripting bug (CVE-2021-35208) that can be triggered in a victim’s browser when viewing an incoming email. The malicious email would contain a crafted JavaScript payload that, when executed, would provide an attacker with access to all emails of the victim, as well as to their webmail session.” reads the post published by Sonarsource. “With this, other features of Zimbra could be accessed and further attacks could be launched.”

“An attacker could place HTML containing executable JavaScript inside element attributes. This markup becomes unescaped, causing arbitrary markup to be injected into the document.” reads the description for the vulnerability.

The second flaw, tracked as CVE-2021-35209 (CVSS score: 6.1) is a proxy Servlet Open Redirect vulnerability that resides in ProxyServlet.java in the /proxy servlet in Zimbra Collaboration Suite 8.8 before 8.8.15 Patch 23 and 9.x before 9.0.0 Patch 16.

“The second vulnerability is an interesting bypass of an allow-list that leads to a powerful Server-Side Request Forgery vulnerability (CVE-2021-35209). It can be exploited by an authenticated member of an organization with any permission role, which means that it can be combined with the first vulnerability. A remote attacker is then able to extract, for example, Google Cloud API Tokens or AWS IAM credentials from instances within the cloud infrastructure.”states Sonarsource.

“The value of the X-Host header overwrites the value of the Host header in proxied requests. The value of X-Host header is not checked against the whitelist of hosts Zimbra is allowed to proxy to (the zimbraProxyAllowedDomains setting).” reads the advisory for this issue.

The vulnerabilities have been addressed with the release of Zimbra versions 8.8.15 Patch 23 and 9.0.0 Patch 16.

“A combination of these vulnerabilities could enable an unauthenticated attacker to compromise a complete Zimbra webmail server of a targeted organization,” said Scannell. “As a result, an attacker would gain unrestricted access to all sent and received emails of all employees.”

Zimbra also published an alert to warn its customers about these vulnerabilities.

Below the timeline for these flaws:

DateAction
2021-05-19We reached out to the Zimbra Security team and exchanged PGP keys
2021-05-19The vendor responded with a PGP key
2021-05-20We sent the vendor an advisory regarding the SSRF vulnerability
2021-05-22We sent the vendor an advisory regarding the XSS vulnerability
2021-05-24The vendor confirmed receipt of the details
2021-06-28Zimbra released patches for both vulnerabilities
[adrotate banner=”9″][adrotate banner=”12″]

Pierluigi Paganini

(SecurityAffairs – hacking)

[adrotate banner=”5″]

[adrotate banner=”13″]


facebook linkedin twitter

Cybersecurity cybersecurity news Hacking hacking news information security news Pierluigi Paganini Security Affairs Security News SSRF XSS Zimbra

you might also like

Pierluigi Paganini July 11, 2025
U.S. CISA adds Citrix NetScaler ADC and Gateway flaw to its Known Exploited Vulnerabilities catalog
Read more
Pierluigi Paganini July 10, 2025
UK NCA arrested four people over M&S, Co-op cyberattacks
Read more

leave a comment

newsletter

Subscribe to my email list and stay
up-to-date!

    recent articles

    Athlete or Hacker? Russian basketball player accused in U.S. ransomware case

    Uncategorized / July 11, 2025

    U.S. CISA adds Citrix NetScaler ADC and Gateway flaw to its Known Exploited Vulnerabilities catalog

    Hacking / July 11, 2025

    UK NCA arrested four people over M&S, Co-op cyberattacks

    Cyber Crime / July 10, 2025

    PerfektBlue Bluetooth attack allows hacking infotainment systems of Mercedes, Volkswagen, and Skoda

    Hacking / July 10, 2025

    Qantas data breach impacted 5.7 million individuals

    Data Breach / July 10, 2025

    To contact me write an email to:

    Pierluigi Paganini :
    pierluigi.paganini@securityaffairs.co

    LEARN MORE

    QUICK LINKS

    • Home
    • Cyber Crime
    • Cyber warfare
    • APT
    • Data Breach
    • Deep Web
    • Digital ID
    • Hacking
    • Hacktivism
    • Intelligence
    • Internet of Things
    • Laws and regulations
    • Malware
    • Mobile
    • Reports
    • Security
    • Social Networks
    • Terrorism
    • ICS-SCADA
    • POLICIES
    • Contact me

    Copyright@securityaffairs 2024

    We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. By clicking “Accept All”, you consent to the use of ALL the cookies. However, you may visit "Cookie Settings" to provide a controlled consent.
    Cookie SettingsAccept All
    Manage consent

    Privacy Overview

    This website uses cookies to improve your experience while you navigate through the website. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities...
    Necessary
    Always Enabled
    Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.
    Non-necessary
    Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.
    SAVE & ACCEPT