Preface: Linux mainly uses a paging mechanism to achieve virtual memory management. The size of the memory page is PAGE_SIZE bytes instead of 4 KB. On different platforms, the page size can range from 4 KB to 64 KB.

Background: The Aspeed BMC family which is what is used on OpenPOWER machines and a number of x86 as well is typically connected to the host via an LPC (Low Pin Count) bus (among others).

The check mixes pages (vm_pgoff) with bytes (vm_start, vm_end) on one side of the comparison, and uses resource address (rather than just the resource size) on the other side of the comparison. This can allow malicious userspace to easily bypass the boundary check and map pages that are located outside memory-region reserved by the driver.

Vulnerability details: CVE-2021-42252 – An issue was discovered in aspeed_lpc_ctrl_mmap in drivers/soc/aspeed/aspeed-lpc-ctrl.c in the Linux kernel before 5.14.6. Local attackers able to access the Aspeed LPC control interface could overwrite memory in the kernel and potentially execute privileges, aka CID-b49a0e69a7b1. This occurs because a certain comparison uses values that are not memory sizes.

Reminder: Hardware filter in the southbridge perhaps not easy to detect attacker exploit the vulnerability.

Official announcement:Please refer to the website for details – https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b49a0e69a7b1a68c8d3f64097d06dabb770fec96

Remark: Seems no proof of concept disclosed till now. Refer to official details, it is a local attack. But this design flaw cause by memory corruption error trigger privilege escalation. Furthermore it is running on Linux. Therefore exploit the design flaw through 3rd party API then triggers the vulnerability still have possibilities.

Preface: the most famous UTF-8 attack was against unpatched web server.

Background: The most common users of Apache HTTP Server are from Small Businesses and the Information Technology & Services industry. Perhaps

How to Check the Apache Version?

1. Open terminal application on your Linux, Windows/WSL or macOS desktop.
2. Login to remote server using the ssh command.
3. To see Apache version on a Debian/Ubuntu Linux, run: apache2 -v.
4. For CentOS/RHEL/Fedora Linux server, type command: httpd -v.

Vulnerability details: The server didn’t correctly handle contents in the URL. So the contain contained invalid UTF-8 representation of the [/] character. Such an invalid UTF-8 escape is often referred to as an overlong sequence. Therefore it provide an opportunity to the attacker. On 6th Oct,2021, Apache released Apache HTTP 2.4.50 to fix an actively exploited path traversal vulnerability in version 2.4.49 (tracked as CVE-2021-41773). This flaw allows threat actors to view the contents of files stored on a vulnerable server. Please refer to the official website for announcements – https://httpd.apache.org/security/vulnerabilities_24.html#CVE-2021-42013

Preface: BPF is available on most Unix-like operating systems and eBPF for Linux and for Microsoft Windows. In addition, if the driver for the network interface supports promiscuous mode, it allows the interface to be put into that mode so that all packets on the network can be received, even those destined to other hosts.

Background: The Berkeley Packet Filter (BPF) is a technology used in certain computer operating systems for programs that need to, among other things, analyze network traffic (and eBPF is an extended BPF JIT virtual machine in the Linux kernel). It provides a raw interface to data link layers, permitting raw link-layer packets to be sent and received.

Vulnerability details: CVE-2021-29249 prealloc_elems_and_freelist in kernel/bpf/stackmap.c in the Linux kernel through 5.14.9 allows unprivileged users to trigger an eBPF multiplication integer overflow with a resultant out-of-bounds write.

In 32-bit architecture, the result of sizeof() is a 32-bit integer so the expression becomes the multiplication between two 32-bit integers which can potentially leads to integer overflow. As a result, bpf_map_area_alloc() allocates less memory than needed.

Remedy: Correct this by casting 1 operand to u64 (See attached picture for details).

Point of view: More than 20 years ago, the firewall function was independent, excluding the firewall policy service and vpn function.
The advantage is that when the firewall box is compromised. Nothing else will be found in the box by the attacker.
Over time, the trend of unified threat management has grown. From a technical point of view, it is a multifunctional service.
Maybe it’s hardening. But we can’t say that it is a state machine model (Bell-LaPadula model).

Having said that, the specific design responds to more and more technological developments in the world.
But it is hard to avoid vulnerability occurs due to design weakness.
This time an alert annouced by Sonicwall that an improper access control vulnerability in SMA100 allows a remote unauthenticated attacker to bypass the path traversal checks and delete an arbitrary file potentially resulting in a reboot to factory default settings. This defect can do a DoS attack.

One of the possibilities encounter this defect: Incorrect configuration of aliases may allow an attacker to read files stored outside the target folder. For more details, please refer to attached diagram.

Official announcement: Please refer to link – https://www.sonicwall.com/support/product-notification/security-notice-critical-arbitrary-file-delete-vulnerability-in-sonicwall-sma-100-series-appliances/210819124854603/

Preface: Cryptocurrency look like myth. Someone avoid to use. But somebody like it. If Cryptocurrency only provide payment function. That is no investment value. Furthermore if someone going to transfer money will be know who is sender and recipient. If it come true, what is the result?

Background: BTCPay Server is an open source, P2P payment processor for Bitcoin and other cryptocurrencies where users can self-host their own server and effectively process their own payments.

Quick and easy setup (for individual and retail business): You just open an account on BTCpayserver. it is web GUI and internet everywhere. So, your customer can pay to you by cryptocurrency.

Users have even built web based point of sales payment solutions using the project. Physical stores can leverage the PoS app for accepting crypto payments. BTCPay Server is code, not a company. There is no third-party between a merchant and a customer. The merchant is always in full control of their funds. There are no processing or subscription fees.

Vulnerability details: BTCpayserver is vulnerable to Improper Neutralization of Input During Web Page Generation (‘Cross-site Scripting’). So called Cross-site Scripting, btcpayserver” stored XSS, also known as persistent XSS. In stored XSS, the malicious code is stored on the server of the application. Stored XSS is possible only when the application is designed to store user input. The attacker would inject the code through requests to the application.

Cause: During page generation, the application does not prevent the data from containing content that is executable by a web browser, hsuch as JavaScript, HTML tags, HTML attributes. For details of vulnerability , please refer to attached diagram.

Official details: – https://nvd.nist.gov/vuln/detail/CVE-2021-3830

Preface: Rapid7 Labs estimates there are over 2,700 vulnerable vCenter servers exposed to the public internet.

Background: As of May 1 2020, the Pivotal Telemetry program is governed by VMware’s Customer Experience Improvement Program.
Data and continuous feedback loops play an important role in shaping the way Pivotal builds software.

VMware analytics service consists of components that gather and upload telemetry data from various vSphere components to the VMware Analytics Cloud and manage the Customer Experience Improvement Program (CEIP).

Vulnerability details: CVE-2021-22005 (CVSS score of 9.8) – It is an arbitrary file upload vulnerability in the Analytics service, which can be used to execute commands and software on the vCenter Server Appliance. A malicious actor with network access to port 443 on vCenter Server could exploit it by uploading a specially crafted file.

Observation: Since it can upload telemetry data by analytics service. So, attacker might do the following:

Unauthenticated OVA File Upload RCE – Exploits an unauthenticated OVA file upload and path traversal in vCenter Server to write a JSP payload to a web-accessible directory.

Official announcement – VMware has disclosed a critical bug in its flagship vSphere and vCenter products and urged users to drop everything and patch it. The virtualization giant also offered a workaround. For more details, please refer to the link – https://www.vmware.com/security/advisories/VMSA-2021-0020.html

Preface: As we know that Kubernetes (K8s) is a container orchestration tool and Docker helps to create a container that is managed by us using Kubernetes.

Background: What is subPath in volume mount?
Subpath references files or directories that are controlled by the user, not the system. Volumes can be shared by containers that are brought up at different times in the Pod lifecycle, including by different Pods.
Kubernetes passes host paths to the container runtime to bind mount into the container.

Vulnerability details: A security issue was discovered in Kubernetes where a user may be able to create a container with subpath volume mounts to access files & directories outside of the volume, including on the host filesystem.

The root cause of the problem: K8S doesn’t use the mount syscall directly but it uses the mount command, and the default behavior of utils-linux mount is to resolve symlink.

Highlight: Don’t canonicalize paths. The mount command canonicalizes all paths (from command line or fstab) by default.

Remediation: To mitigate this vulnerability without upgrading kubelet, you can disable the VolumeSubpath feature gate on kubelet and kube-apiserver, and remove any existing Pods making use of the feature. Please refer to the attached picture for details.

Reference: Feature gates are a set of key=value pairs that describe Kubernetes features. You can turn these features on or off using the –feature-gates command line flag on each Kubernetes component.

Preface: With storage zones controllers, the ShareFile Software-as-a-Service (SaaS) cloud storage also offers private storage for ShareFile data, which is known as storage zones.

What is the difference between Dropbox and ShareFile?
The goal of ShareFile is to help your team easily share, sync and store large files from any device without compromising important data. And unlike Dropbox, ShareFile provides the security, visibility and access your business needs from a single cloud-based dashboard.

Background: What is user enumeration?

User enumeration allows attackers to conduct dictionary attacks against systems and reveals information about who has access to them.

Since below services are commonly accessible from the Internet, and often use the organisation’s internal Active Directory (AD) for authentication, this creates a situation where an attacker on the Internet can easily identify usernames from an internal Windows domain.

• Office 365 ActiveSync
• Active Directory Federated Services (ADFS) single sign-on

Without a user enumeration flaw to receive a list of users, these attacks become difficult. Attacker make use of nmap in common way (e.g. $ nmap -p139,445 –script smb-enum-users )

Additional: Other than that, CVE-2021-22941 is the hottest matter this week . A security issue has been identified in Citrix ShareFile storage zones controller which, if exploited, would allow an unauthenticated attacker to remotely compromise the storage zones controller. The official announcement can be find in this link – https://support.citrix.com/article/CTX328123

Ref: The flaws (user enumeration) have been exposing internal corporate networks to attacks for years, yet are undetected by leading vulnerability scanners.

Preface: Did you check your JMS Security Authorization, fix your JMS application immediately.

Background: The basic building blocks of a JMS application are:

• Administered objects: connection factories and destinations
• Connections
• Sessions
• Message producers
• Message consumers
• Messages

The JMS Connector Service is an enterprise messaging system that provides a way for business applications to exchange data
without needing to be directly connected to each other. The communication is obtained using messages. It allows different
message models like Point-to-Point Messaging or Publish-Subscribe scenarios.

Vulnerability details: Missing Authorization check in SAP NetWeaver Application Server for Java (JMS Connector Service)
The JMS Security Mechanism can helps you to protect your JMS application. By defining JMS actions for some API methods (such as createProducer(), createConsumer(), and so on) and assign permission to different user roles. In fact, it can minimize the risk.
In order to avoid unforseen issue happen in future. It is highly recommended to following vendor instruction to do the patching as early as possible.

Affected products – SAP NetWeaver Application Server Java (JMS Connector Service) , Versions – 7.11, 7.20, 7.30, 7.31, 7.40, 7.50

Official announcement – https://wiki.scn.sap.com/wiki/pages/viewpage.action?pageId=585106405