Security | Threat Detection | Cyberattacks | DevSecOps | Compliance

On July 19, 2025, a critical remote code execution (RCE) vulnerability (CVE-2025-53770, also referred to as ToolShell) was publicly disclosed, impacting on-premises Microsoft SharePoint Server installations. This vulnerability allows unauthenticated attackers to execute arbitrary code remotely by leveraging insecure deserialization techniques.

The cybersecurity landscape witnessed a perfect storm in July 2025 when multiple critical SharePoint vulnerabilities collided with sophisticated IIS module-based persistence techniques, creating a nightmare scenario for enterprise defenders. CVE-2025-53770, CVE-2025-53771, CVE-2025-49704, and CVE-2025-49706 are being actively exploited by sophisticated threat actors, but the real danger extends far beyond the initial exploitation phase.

On July 22, 2025, Microsoft published an overview of a series of critical vulnerabilities affecting Microsoft SharePoint Server (CVE-2025-49704, CVE-2025-49706, CVE-2025-53770, and CVE-2025-53771). These vulnerabilities opened a dangerous window for threat actors to gain access to internal resources, execute code remotely, and take over SharePoint deployments.

Hats off to the great work the community and industry has done regarding the “ToolShell” attack against Microsoft’s On-Premise SharePoint servers. The goal of this article is to build on that great work and help Sumo Logic customers with on-prem SharePoint servers investigate and identify evidence within their environments.

The adage ‘an ounce of prevention is better than a pound of cure’ applies to AppSec vulnerability management. Traditionally, AppSec has focused on a reactive ‘curing flaws’ paradigm, identifying and fixing vulnerabilities after they have occurred. However, the never-ending escalation between threats and security leads to alert fatigue and security debt.

On July 23, 2025, Mitel released fixes for a critical authentication bypass vulnerability in the Provisioning Manager component of Mitel MiVoice MX-ONE, a communication platform used for enterprise voice and collaboration services. The vulnerability allows unauthenticated remote threat actors to gain unauthorized access to publicly exposed Mitel voice systems and access user or administrator accounts due to improper access controls.

A newly disclosed vulnerability, CVE-2025-53770, has sent shockwaves through the enterprise IT and cybersecurity community. Affecting on-premises Microsoft SharePoint Server, this critical flaw enables unauthenticated remote code execution (RCE) through insecure deserialization of untrusted data. With a CVSS v3.1 score of 9.8, it represents one of the most severe threats to SharePoint deployments in recent years.

In 2023, a critical vulnerability in MOVEit Transfer software (CVE-2023-34362) was weaponized by the Cl0p ransomware group, leading to a substantial leak of sensitive employee data from major global corporations. The flaw in MOVEit allowed attackers to bypass authentication and access secure files, resulting in a far-reaching data breach that impacted various sectors including finance, healthcare, government, and retail.

Security teams juggle a multitude of tools to keep their organizations safe. One platform scans for exposed assets, another tracks vulnerabilities, and yet another manages remediation tasks – and the list goes on. Organizations use an average of 38 different security products, leading to fragmented processes and a lot of “noise” in the form of findings. It’s no surprise that 85% of security professionals say all this noise makes it challenging to reduce risk quickly.