November “In the Trend of VM” (#21): vulnerabilities in Windows, SharePoint, Redis, XWiki, Zimbra Collaboration, and Linux. The usual monthly roundup. After several months, here’s a big one. 🔥
About Cross Site Scripting – Zimbra Collaboration (CVE-2025-27915) vulnerability.Zimbra Collaboration is a collaboration software suite, somewhat similar to Microsoft Exchange. Exploiting this vulnerability in the web mail client (Classic Web Client) allows an unauthenticated attacker to execute arbitrary JavaScript in the context of the victim’s session. To do this, the attacker only needs to send an email with a specially crafted ICS file (iCalendar). The payload is triggered when the message is viewed in the web interface.
⚙️ The vulnerability was patched on January 27 in versions 9.0.0 Patch 44, 10.0.13, 10.1.5, as well as in the unofficial free Zimbra FOSS build from Maldua.
🛠 On September 30, StrikeReady Labs published a vulnerability analysis with a public exploit.
👾 StrikeReady Labs reported the vulnerability was exploited against Brazil’s military in January, before the patch was released. The vulnerability was added to CISA KEV on October 7.
June “In the Trend of VM” (#16): vulnerabilities in Microsoft Windows, Apache HTTP Server, the web interfaces of MDaemon and Zimbra, and the 7-Zip archiver. A traditional monthly vulnerability roundup. 🙂
About Cross Site Scripting – Zimbra Collaboration (CVE-2024-27443) vulnerability. Zimbra Collaboration is a collaboration software suite that includes a mail server and a web client. An attacker can send an email containing a specially crafted calendar header with an embedded payload. If the user opens the email in the classic Zimbra web interface, the malicious JavaScript code will be executed in the context of the web browser window.
The vulnerability was fixed on February 28, 2024. As with the MDaemon vulnerability, exploitation of this vulnerability in the wild was reported by ESET researchers (Operation “RoundPress”). They discovered attacks in 2024, after the patch had already been released. The malicious code allowed attackers to steal credentials, extract contacts and settings, and gain access to email messages.
ESET published information about the attacks and a PoC exploit only on May 15, 2025. 🤷♂️ The flaw was added to the CISA KEV catalog on May 19.
Last Week’s Security news: Serious Sam in Metasploit, PetitPotam, Zimbra Hijack, Joint Advisory TOP30 CVEs. Hello everyone! Last Week’s Security News, July 26 – August 1.
Serious Sam in Metasploit
Last week I talked about the Serious Sam vulnerability (CVE-2021-36934), also known as HiveNightmare. The name HiveNightmare comes from the fact that Windows stores its registry data in a small number of proprietary database files called hives. Due to mismanagement of SAM and SYSTEM hives in Windows 10, it is possible for an unprivileged user to read those files and then, for example, extract the account password hashes. An exploit for this vulnerability is now available in Metasploit and it will be much easier for attackers to exploit this vulnerability. The issues is still under investigation by Microsoft and a patch is not currently available, only the list of vulnerable OS versions, however a workaround has been provided.
PetitPotam
At the beginning of last week, PetitPotam (Little Hippo) attack made a lot of noise. It could force remote Windows systems to reveal password hashes that could then be easily cracked.
“The PetitPotam bug is tied to the Windows operating system and the abuse of a remote access protocol called Encrypting File System Remote Protocol (MS-EFSRPC). The protocol is designed to allow Windows systems to access remote encrypted data stores, allowing for management of the data while enforcing access control policies. […] The PetitPotam PoC is a form of manipulator-in-the-middle (MitM) attack against Microsoft’s NTLM authentication system. Next, an attacker uses the file-sharing protocol Server Message Block (SMB) to request access to a remote system’s MS-EFSRPC interface. According to [security researcher Gilles Lionel], this forces the targeted computer to initiate an authentication procedure and share its authentication details via NTLM.
In response to the public availability of the PoC, Microsoft was quick to respond, outlining several mitigation options. For starters, Microsoft recommends disabling NTLM authentication on Windows domain controllers. It also suggests enabling the Extended Protection for Authentication (EPA) feature on AD CS services.”
But there won’t be any special fix. Microsoft: “PetitPotam is a classic NTLM Relay Attack, and such attacks have been previously documented by Microsoft along with numerous mitigation options to protect customers.”
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