Earlier this week Apple issued an update to macOS Big Sur bringing it up to version 11.3. This update included a security fix for a vulnerability within the macOS Gatekeeper security system, and given the ID of “CVE 2021-30657”. This vulnerability was disclosed to Apple by an expert macOS Security Researcher Cedric Owens (Twitter: @cedowens, GitHub: cedowens).
Recently a heap-based buffer overflow vulnerability was discovered in the sudo utility by Qualys. Sudo is a command-line utility that allows a user to run commands in the context of other users with proper authentication. The vulnerability lets any user escalate the privileges to the root user. Qualys has shared technical details in their blog post, so in this post I’ll focus on how osquery and Uptycs can be used to detect the exploit and unpatched systems
The Uptycs threat research team recently came across multiple document samples that download Revenge RAT. The campaign currently seems to be active in Brazil. All of the malware samples we received have the same properties. One of the samples we received has the name “Rooming List Reservas para 3 Familias.docx” (SHA-256: 91611ac2268d9bf7b7cb2e71976c630f6b4bfdbb68774420bf01fd1493ed28c7). The document has only a few detections in VirusTotal.
Uptycs' threat research team identified an XLS document that downloaded a highly vicious payload named Warzone RAT. The payload, also known as “Ave Maria stealer,” can steal credentials and log keystrokes on the victim’s machine. Checkpoint mentioned Warzone early this year when the malware was in its early stage of development.
SecOps and IT administrators have seen plenty of information regarding the GRUB2 BootHole vulnerability. In addition to BootHole, several low to moderate vulnerabilities were also discovered and fixed. While a key recommendation for mitigation is to install OS updates and patches, vendor patches should be carefully tested and incrementally applied to vulnerable assets. Updating the Secure Boot Forbidden Signature Database (dbx) has caused issues in the past. Initial GRUB2 patches from Red Hat caused boot issues for some RHEL and CentOS machines.
Microsoft released multiple security updates on Tuesday, July 14, including one for a remote code execution vulnerability for their DNS server.