Category Archives: Potential Risk of CVE

About IOCTL handlers (Buffer Copy without Checking Size of Input (Classic Buffer Overflow)) – 7th Dec 2021

Preface: If it is a integer, just use it directly. If it is a pointer, need to check for valid user address:
int access_ok(int type, const void *addr, unsigned long size);

Background: IOCTL is referred as Input and Output Control, which is used to talk with device drivers. IOCTL is a system call where system call is the programmatic way in which a computer program in user space
requests a service from the kernel space of the operating system.

According to Oracle Solaris 11 Information Library article. So called Well Known ioctl Interfaces. Many ioctl(9E) operations are common to a class of device drivers. For example, most disk drivers implement many of the dkio(7I) family of ioctls. Many of these interfaces copy in or copy out data structures from the kernel, and some of these data structures have changed size in the LP64 data model.

Perhaps the vulnerability this time not related to Oracle 11. Since Oracle is outdated and end-of-life.

Vulnerability details: SentinelLabs has discovered a number of high severity flaws in driver software affecting numerous cloud services. These vulnerabilities originated from a library developed and provided by Eltima, which is in use by several cloud providers. These vulnerabilities affect multiple products. Attacker choose the code deals with a user buffer of type METHOD_NEITHER (Type3InputBuffer), if it IOCTL handler do not have validating. It will trigger the vulnerability of the IOCTL handlers 0x22001B. If you are interested, please refer to the link – https://www.sentinelone.com/labs/usb-over-ethernet-multiple-privilege-escalation-vulnerabilities-in-aws-and-other-major-cloud-services/

Certain versions of WebHMI from Distributed Data systems has vulnerabilities occurs.The manufacturer recommends upgrading to version 4.1. (6th Dec 2021)

Preface: CISA Releases Security Advisory on WebHMI Vulnerabilities – https://us-cert.cisa.gov/ics/advisories/icsa-21-336-03

Background: The company Distributed Data Systems LLC is well-known in Ukraine and abroad for products with WebHMI and 7bit brands for remote monitoring and control of industrial equipment in Industry 4.0 format.

Remark: 7Bit ModBus Proxy is a caching gateway from ModBus TCP protocol to Modbus RTU.

SCADA is a powerful control system that is designed to collect, analyze, and visualize data from industrial equipment. Web-based HMIs allow users to monitor and control devices and processes at a distance. WebHMI is a SCADA-system with built-in web server that allows you to monitor and control any automation system on the local network and via the Internet from your computer and mobile devices.

Vulnerability details: The WebHMI itself encountered two different vulnerabilities includes Authentication Bypass by Primary Weakness and Unrestricted Upload of File with Dangerous Type.

CVE-2021-43931 The authentication algorithm of the WebHMI portal is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.

CVE-2021-43936 The software allows the attacker to upload or transfer files of dangerous types to the WebHMI portal, that may be automatically processed within the product’s environment or lead to arbitrary code execution.

The following information is our speculation on the cause of the vulnerabilities.

CVE-2021-43931 – Insufficient Session Expiration is a security flaw that lets an application permit an attacker to reuse old session credentials or session IDs, thus exposing an application to attacks that steal or reuse users’ session identifiers.
CVE-2021-43936 – Sneaking in a malicious script is easier than using compiled malware. Once these scripts make their way to the target host, they are executed in a safe location where they cannot be flagged, such as the /tmp folder. Generally, these scripts do not carry out anything malicious on their own, although they do connect to the command-and-control (C&C) server to download malware.

CVE-2021-38575 – NetworkPkg/IScsiDxe has remotely exploitable buffer overflows. For a bug discovered half a year ago, CVE assigned a CVE number this month.(1-12-2021)

Preface: If a network interface controller is intended to be used as a boot device for a UEFI operating system or UEFI applications, then a UEFI Driver must be implemented that produces Network Interface Identifier Protocol and UNDI, the Simple Network Protocol, or the Managed Network Protocol.

Background: Tianocore EDK II is the UEFI reference implementation by Intel. EDK is the abbreviation for EFI Development Kit and is developed by the TianoCore community.

UEFI stands for Unified Extensible Firmware Interface. It does the same job as a BIOS, but with difference. It stores all data about initialization and startup. UEFI supports drive sizes upto 9 zettabytes, whereas BIOS only supports 2.2 terabytes. UEFI provides faster boot time.

UEFI also includes TCP (the latest version of UEFI from IIRC supports booting via HTTP, similar to iPXE).

Disadvantages of UEFI?

  • 64-bit are necessary.
  • Virus and Trojan threat due to network support, since UEFI doesn’t have anti-virus software.

Vulnerability details: Certain versions of EDK II from TianoCore contain vulnerability (NetworkPkg/IScsiDxe has remotely exploitable buffer overflows). The fact is that potential integer overflow in IScsiBinToHex().

Reason: EFI_BUFFER_TOO_SMALL The binary buffer is too small to hold the converted data.

Official details: Please refer to the link – https://bugzilla.tianocore.org/show_bug.cgi?id=3356

CVE-2021-41256 The Android version of the Nextcloud news app has security issues (30-11-2021)

Preface: Nextcloud is a suite of client-server software for creating and using file hosting services. It is enterprise-ready with comprehensive support options. Being free and open-source software, anyone is allowed to install and operate it on their own private server devices.

Background: The Nextcloud News Reader App makes it possible to synchronize feeds between Android and the Nextcloud News App. In order to use this app , you will need to have a nextcloud instance running with the news app installed.

About Nextcloud 17. The main novelty of the new version of Nextcloud is that the addition of the “remote wipe” feature is very eye-catching. This allows users to delete files on mobile devices. The administrator will delete data from all devices of a given user.

Unlike Google Drive, Dropbox, Yandex.Disk and box.net services, the ownCloud and Nextcloud projects provide users with complete control over their data: the information is not tied to an external closed cloud storage system, but the user controls the device.

Vulnerability details: How to switch from the original first MainActivity to the ResultActivity we just generated? The answer is to use Intent,

In affected versions the Nextcloud News for Android app has a security issue by which a malicious application installed on the same device can send it an arbitrary Intent that gets reflected back, unintentionally giving read and write access to non-exported Content Providers in Nextcloud News for Android.

Remedy: Users should upgrade to version 0.9.9.63 or higher as soon as possible.

Observation: In Android, there are many specific security related issues that pertain only to certain technologies such as Activities or SQLite. If a developer does not have enough knowledge about each of the different security issues regarding each technology when designing and coding, then unexpected vulnerabilities may arise.

Repair details: please refer to the link https://github.com/nextcloud/news-android/commit/05449cb666059af7de2302df9d5c02997a23df85

About CVE-2021-3802, Fedora & Ubuntu already address this matter, it is a reminder (29-11-2021).

Preface: (2021-07-30) Reported to KDE and GNOME development teams – In response, patches for both kio and glib were implemented.
However, both projects rely mainly on udisks and use own code only as fallback.

Background: Ubuntu used to have Unity desktop in its default edition but it switched to GNOME desktop since version 17.10 release.
Ubuntu offers several desktop flavors and the KDE version is called Kubuntu. GNOME is the default desktop for Fedora and KDE is the default desktop for OpenSUSE. Depending on how old your Linux distribution is you might have udisks or udisks2 (fourth process) and then you have the udev daemon (second process).

One of the characteristics of Dbus, if you plug in a USB storage device. Dbus and UDisks2 will notified you device is ready.


Remark (a): udisks2 is used by KDE and GNOME nowadays at least (since years). udisks (1) is outdated/obsolete.

Remark (b): The one is udisks which deals with storage devices like USB sticks and the like. The second is udev, a daemon that deals with all kind of devices from PCI boards to the keyboard and mouse (including everything that udisks deals with).

Vulnerability details: Several user-accessible mount helpers use insecure defaults which allow ext2/3/4 file systems to cause a denial of service (kernel panic) upon mounting a crafted image.

Official announcementhttps://bugzilla.redhat.com/show_bug.cgi?id=2003649

Udisks2 hides certain devices from the user by default. You can enter the following directory for review:

Fedora – /usr/lib/udev/rules[.]d/80-udisks2[.]rules

CVE-2021-23654 – This affects all versions of package html-to-csv. The flaw let threat actor can embed or generate a malicious link or execute commands via CSV files (26-11-2021)

Preface: CSV file is a useful thing in today’s world when we are talking about machine learning, data handling, and data visualization.

Background: There are many Raw storage bucket for big data analytic. You might store it in a text format such as JavaScript Object Notation (JSON) or comma-separated values (CSV), or perhaps even Apache Avro. Most people prefer to store it in either JSON or CSV files. CSV format is about half the size of the JSON and another format file. It helps in reducing the bandwidth, and the size of the below would be very less. Therefore, csv is one of the important data types used in the field of data analysis.

Vulnerability details: When there is a formula embedded in a HTML page, it gets accepted without any validation and the same would be pushed while converting it into a CSV file. Through this a malicious actor can embed or generate a malicious link or execute commands via CSV files.

Impact: This affects all versions of package html-to-csv.

Official details: Please refer to the link for details – https://security.snyk.io/vuln/SNYK-PYTHON-HTMLTOCSV-1582784

Reference: BeautifulSoup parsing flaw – None of the parsing error is caused due to BeautifulSoup. It is because of external parser use (html5lib, lxml) since BeautifulSoup doesn’t contain any parser code. One way to resolve above parsing error is to use another parser.

Python built-in HTML parser causes two most common parse errors, HTMLParser.HTMLParserError: malformed start tag and HTMLParser.HTMLParserError: bad end tag and to resolve this, is to use another parser mainly: lxml or html5lib.

About Zoom vulnerability CVE-2021-34423 (25-11-2021)

Preface: What if you need to decide to buy remote meeting software? In front of you, Microsoft Teams, Zoom, and Cisco WebEx. What is your final decision? Or you decide to buy all, because all three items have design weakness but it is under enhancement.

Background: What is H.323 suite H.323 is a standard developed by the ITU. It specifies packet-based multimedia communications systems across networks, which might not provide any Qos guarantees. H.323 suite is family of standards that includes many other ITU standards (See attached diagram for details).

A Room Connector (Zoom) can also call out to a H.323 or SIP device to join a Zoom cloud meeting. Use this API to add a H.323/SIP device to your Zoom account.

A H.323 or SIP device can make a video call to a to join a Zoom cloud meeting.

Vulnerability details: A buffer overflow vulnerability was discovered in the products listed in the “Affected Products” section of this bulletin. This can potentially allow a malicious actor to crash the service or application, or leverage this vulnerability to execute arbitrary code.

Observation 1: The vulnerability is due to a failure to properly validate certain fields in an H.323 protocol suite message. When processing the malicious message, the affected device may attempt to access an invalid memory region, resulting in a crash. An attacker who can submit an H.323 packet designed to trigger the vulnerability could cause the affected device to crash and restart.

Observation 2: Believed that Zoom products contain vulnerabilities in the processing of Session Initiation Protocol (SIP) INVITE messages. These vulnerabilities were identified by the University of Oulu Secure Programming Group (OUSPG) “PROTOS” Test Suite for SIP and can be repeatedly exploited to produce a denial of service.

Official announcement: https://explore.zoom.us/en/trust/security/security-bulletin/

About CVE-2021-21980 – VMware found SSRF, arbitrary file read flaws in vCenter Server (24-11-2021)

Preface: VMware Flash End of Life and Supportability (78589) – https://kb.vmware.com/s/article/78589

Background: Flex is a powerful, open source application framework that allows you to build mobile applications for iOS, Android, and BlackBerry Tablet OS devices, as well as traditional applications for browsers and desktops using the same programming model, tool, and codebase. From a platform perspective, the vSphere Web Client is based on Apache Flex, which used to be called Adobe Flex. Adobe Flex is a Flash-based platform so it requires Adobe Flash to be installed in order to run.

Ref: Flex uses MXML to define UI layout and other non-visual static aspects, ActionScript to address dynamic aspects and as code-behind, and requires Adobe AIR or Flash Player at runtime to run the application.

Vulnerability details: VMware has released important security updates to address two vulnerabilities in the vSphere Web Client (FLEX/Flash) portion of vCenter Server. CVE-2021-21980 is an arbitrary file read vulnerability in the vSphere Web Client and CVE-2021-22049 contains an SSRF (Server Side Request Forgery) vulnerability in the vSAN Web Client (vSAN UI) plug-in. An attacker with access to port 443 on vCenter Server could gain access to sensitive information or take control of a system.

The vCenter Server 7.x and Cloud Foundation 4.x release lines are not affected by these vulnerabilities as they do not use the vCenter Server vSphere Web Client (FLEX/Flash).

Official announcement: https://www.vmware.com/security/advisories/VMSA-2021-0027.html

Reminder: So far, Flash/Flex has discovered many design weaknesses. The defects display on attached diagram are not new items, but what do you think is the design defect that the supplier repaired this week, does it include related relationships, or has the supplier discovered a new defect?

CVE-2021-28706 About Xen memory management design weaknesses (24-11-2021)

Preface: Who uses Xen? Amazon Web Services alone runs ½ million virtualized Xen Project instances according to a recent study and other cloud providers such as Rackspace and hosting companies use the hypervisor at extremely large scale. Xen is a type-1 bare-metal hypervisor.

Background: A Xen host will run a number of virtual machines, VMs, or domains (the terms are synonymous on Xen). One of these is in charge of running the rest of the system, and is known as “domain 0”, or “dom0”.
Any other VM is unprivileged, and are known as a “domU” or “guest”.

A hypercall is based on the same concept as a system call. System calls are used by an application to request services from the OS and provide the interface between the application or process and the OS. Hypercalls work the same way, except the hypervisor is used.

Vulnerability details: (Official description) – When a guest is permitted to have close to 16TiB of memory, it may be able to issue hypercalls to increase its memory allocation beyond the administrator established limit. This is a result of a calculation done with 32-bit precision, which may overflow. It would then only be the overflowed (and hence small) number which gets compared against the established upper bound.

Impact: A guest may be able too allocate unbounded amounts of memory to itself. This may result in a Denial of Service (DoS) affecting the entire host.

Workaround: Setting the maximum amount of memory a guest may allocate to strictly less than 1023 GiB will avoid the vulnerability.
 Example: This should work within the DomU:

echo $((4096*1024*1024)) >/proc/xen/balloon

Should resize the memory to 4 GB.

Official article: Please refer to the link – https://xenbits.xenproject.org/xsa/advisory-385.txt

About NVIDIA GPU vulnerabilities -22nd Nov 2021

Preface: NVIDIA, the inventor of the Graphics Processing Unit (GPU) brings visual computing excellence to the embedded world. High performance meets low power with the NVIDIA Tegra processor – get ready for HD video, crisp graphics and unprecedented 3D capabilities, all in one power efficient package.

Background: GPUDirect Storage kernel driver nvidia-fs.ko is a kernel module to orchestrate IO directly from DMA/RDMA capable storage to user allocated GPU memory on NVIDIA Graphics cards. NVIDIA GPU using DMAdirect. There are DMA engines in GPUs and storage-related devices like NVMe drivers and storage controllers but generally not in CPUs. Because of this external extended resources allocation implemented in Nvidia GPU design. So when you open the resource files package (gds-nvidia-fs). You will find two types of RDMA files. The nvfs-rdma[.]c files are source files which will be compiled. The nvfs-rdma[.]h files are used to expose the API of a program to either other part of
that program or other program is you are creating a library.

Remark: Usually, GPUDirect kernel module is set to load by default by the system startup service. If it is not loaded, GPUDirect RDMA would not work, which would result in a very high latency for message communications.

The high-risk scoring items caught my attention (see below):

CVE‑2021‑23201 – NVIDIA GPU and Tegra hardware contain a vulnerability in an internal microcontroller which may allow a user with elevated privileges to generate valid microcode. This could lead to information disclosure, data corruption, or denial of service of the device.

CVE‑2021‑23217 – NVIDIA GPU and Tegra hardware contain a vulnerability in the internal microcontroller which may allow a user with
elevated privileges to instantiate a specifically timed DMA write to corrupt code execution, which may impact confidentiality, integrity,
or availability.

As usual, vendor not convenient to elaborate the vulnerabilities reason in details. However if you are interested of this design weakness.
You can find the hints to narrow down the item then do a summary. Even if it may not be accurate. But there is no harm in doing this research.

Be my guest. Refer to diagram, the well known vulnerabilities is given by dirver (nvlddmkm[.]sys). Nvlddmkm[.]sys error is a well-known error. However I believe the vulnerability occurred this time may extend the impact to other edge. For example CPU (please refer to step 5,6 &7 display on attached diagram).

Official details and remedy: Please refer to the link – https://nvidia.custhelp.com/app/answers/detail/a_id/5263