Category Archives: Cell Phone (iPhone, Android, windows mobile)

Get closer look CVE-2024-39920: About “SnailLoad” issue (5-Jul-2024)

NVD Published Date: 07/03/2024

Preface: How is RTT measured in TCP? Measures the time from sending a packet to getting an acknowledgment packet from the target host.

Background: A new technology standard called “RFC 9293” was released on August 18, 2022.


-Acknowledgment Number:  32 bits – If the ACK control bit is set, this field contains the value of the next sequence number the sender of the segment is expecting to receive.  Once a connection is established, this is always sent.

-There are also methods of “fingerprinting” that can be used to infer the host TCP implementation (operating system) version or platform
information. These collect observations of several aspects, such as
the options present in segments, the ordering of options, the
specific behaviors in the case of various conditions, packet timing,
packet sizing, and other aspects of the protocol that are left to be
determined by an implementer, and can use those observations to
identify information about the host and implementation.

Vulnerability details: The TCP protocol in RFC 9293 has a timing side channel that makes it easier for remote attackers to infer the content of one TCP connection from a client system (to any server), when that client system is concurrently obtaining TCP data at a slow rate from an attacker-controlled server, aka the “SnailLoad” issue. For example, the attack can begin by measuring RTTs via the TCP segments whose role is to provide an ACK control bit and an Acknowledgment Number.

Official announcement: For detail, please refer to link –

CVE-2024-20081: Out-of-bounds write in gnss, response by Mediatek security advisory. (2nd July 2024)

Preface: GPS traditionally refers to the North American Global Positioning System, or satellite positioning system. GNSS is the term for the international multi-constellation satellite system. Therefore, GNSS typically includes GPS, GLONASS, Baidu, Galileo, and any other constellation system.

Background: GNSS positioning modules or chips, as the core component of In-vehicle Infotainment systems, provide position, speed, and time information. GNSS position and speed measurements are integral, especially with respect to moving map navigation.

GNSS are used in all forms of transportation: space stations, aviation, maritime, rail, road and mass transit. Positioning, navigation and timing (PNT) play a critical role in telecommunications, land surveying, law enforcement, emergency response, precision agriculture, mining, finance, scientific research…etc.

Vulnerability details: In gnss service, there is a possible escalation of privilege due to improper certificate validation. This could lead to remote escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS08720039; Issue ID: MSV-1424.

Official announcement: For detail, please refer to link –

CVE-2024-38663: blk-cgroup – fix list corruption from resetting io stat (25-June-2024)

Preface: Android uses cgroups to control and account for system resources such as CPU and memory usage and allocation, with support for Linux kernel cgroups v1 and cgroups v2.

Background: New IO stats are stored in the percpu iostat_cpu within blkcg_gq (blkg). There are multiple blkg’s (one for each block device) attached to each blkcg. The rstat code keeps track of which cpu has IO stats updated, but it doesn’t know which blkg has the updated stats. If there are many block devices in a system, the cost of iterating all the blkg’s to flush out the IO stats can be high. To reduce such overhead, a set of percpu lockless lists (lhead) per blkcg are used to track the set of recently updated iostat_cpu’s since the last flush. An iostat_cpu will be put onto the lockless list on the update side [blk_cgroup_bio_start()] if not there yet and then removed when being flushed [blkcg_rstat_flush()].

References to blkg are gotten and then put back in the process to protect against blkg removal.

Vulnerability details: blk-cgroup: fix list corruption from resetting io stat. Since commit 3b8cc6298724 (“blk-cgroup: Optimize blkcg_rstat_flush()”), each iostat instance is added to blkcg percpu list, so blkcg_reset_stats() can’t reset the stat instance by memset(), otherwise the llist may be corrupted.

Fix the issue by only resetting the counter part.

Official announcement: For detail, please refer to link –

CVE-2024-26926: Kernel – The vulnerability in this section could lead to local escalation of privilege in the kernel with no additional execution privileges needed (6 Jun 2024)

Preface: In linux distributions the term ‘upstream’ (also applied to kernel) refers to the original version (as is released by software developers) of a program/software (kernel in your case) while ‘downstream’ refers to the software provided by linux distribution.

Background: There are many ways to communicate with IPC, such as: Shared Memory, Message Queue, PIPE, FIFO, Unix Socket, etc. A process cannot access another process’s memory. However, the kernel has control over all processes and therefore can expose an interface that enables IPC. In Binder, this interface is the /dev/binder device, which is implemented by the Binder kernel driver.

Ref: A Mutex is a Mutually exclusive flag. It acts as a gate keeper to a section of code allowing one thread in and blocking access to all others.

Vulnerability details:

Kernel -The vulnerability in this section could lead to local escalation of privilege in the kernel with no additional execution privileges needed.

Official announcement: For detail, please refer to link –

Apple security updates on 20th May 2024, But it has not published CVE entries. Observe how Apple handled in the past, maybe you can find it in a CVE few months from now. (27-05-2024)

Preface: Apple released iOS 17.5 and iPadOS 17.5 on May 20, 2024, which fixed multiple security vulnerabilities.  I heard that some users found that photos they had deleted years ago suddenly appeared in recent albums as new photos.

Background: The attached pictures document some rare occurrences. For example, which IOS version still support 32 bit applications last year. Perhaps there is a difference regarding to offical announcement. And suspected that may be is the reason to unsupport 32 bits apps.

Official announcement: Why does deleting pictures return?

According to Apple, the photos that did not fully delete from a user’s device were not synced to iCloud Photos. Those files were only on the device itself. However, the files could have persisted from one device to another when restoring from a backup, performing a device-to-device transfer, or when restoring from an iCloud Backup but not using iCloud Photos.

As for vulnerabilities details in security updates, I will pay close attention to see if they can be found.

There are no published CVE entries for this update.  Please refer to the link for details –

CVE-2024-23354 Memory corruption when the IOCTL call is interrupted by a signal. (24May 2024)

Originally published on May 6, 2024

Preface: The Snapdragon 8 Gen 2 Mobile Platform defines a new premium standard for connected computing. Intelligently engineered with groundbreaking AI across the board, this AI marvel enables truly extraordinary experiences.

Background: A vertex buffer object (VBO) is an OpenGL feature that provides methods for uploading vertex data (position, normal vector, color, etc.) to the video device for non-immediate-mode rendering.

KGSL allocates GPU-shared memory from its own page pool. A VBO is a buffer of memory which the gpu can access. That’s all it is. A VAO is an object that stores vertex bindings. This means that when you call glVertexAttribPointer and friends to describe your vertex format that format information gets stored into the currently bound VAO.

Vulnerability details: Memory corruption when the IOCTL call is interrupted by a signal.

Remedy: The VBO bind operation is often synchronous, and needs to be waited on by the ioctl thread. Allocate the completion struct used to synchronize between the ioctl and bind operation on the heap for simplicity.

Official announcement: Please refer to the link for details –

CVE-2024-21474: Qualcomm did not disclose technical details. Could this situation cause this problem? (6th May 2024)

Preface: The Qualcomm Snapdragon X65 5G Modem is the baseband chipset used in the iPad Pro (11-inch) (4th generation), iPad Pro (12.9-inch) (6th generation), iPhone 14, iPhone 14 Plus, iPhone 14 Pro and iPhone 14 Pro Max.

Background: A power management integrated circuit (PMIC) is used to manage power on an electronic devices or in modules on devices that may have a range of voltages. The PMIC manages battery power charging and sleep modes, DC-to-DC conversion, scaling of voltages down or up, among others.

Vulnerability details: Memory corruption when size of buffer from previous call is used without validation or re-initialization.

Vulnerability Type: CWE-121 Stack-based Buffer Overflow

Official announcement: Please refer to the link for details –

Android Security Bulletin – May 2024 There’s a lot you can explore (9 May 2024)

Preface: Heard that Long-term support (LTS) for Linux kernels is being reduced from six to two years now.

Background: Greg Kroah-Hartman is a major Linux kernel developer. As of April 2013, he is the Linux kernel maintainer for the -stable branch, the staging subsystem, USB, driver core, debugfs, kref, kobject, and the sysfs kernel subsystems, Userspace I/O, and TTY layer.

What will be the next LTS kernel?

But in any event Greg Kroah-Hartman has decided to go ahead and declare Linux 6.6 as the newest LTS kernel. has been updated to reflect Linux 6.6 LTS. The current plan is for Linux 6.6 to be maintained until going end-of-life in December 2026: the same time Linux 6.1, 5.15, and 5.10 will reach end-of-life.

Android Security Bulletin—May 2024 (Published May 6, 2024)

The diagram above shows that kernel versions have been updated. Kernel version updates are dependent on the version of Android OS at the time of device launch. Please refer to the following link for details:

CVE-2024-1067: Mali GPU Kernel Driver allows improper GPU memory processing operations (8 May 2024)

Date of issue: 3rd May 2024

Preface: The Mali-G720 and Mali-G620 GPUs complete the world-class GPU portfolio for a wide range of consumer devices. After four generations of GPUs on the fourth-generation Valhall architecture, the latest Arm GPUs are built on a new fifth-generation GPU architecture (called Gen 5).

Background: The New 5th Gen Arm GPU Architecture

The 5th Gen GPU architecture introduces a key feature called Deferred Vertex Shading (DVS), which revolutionizes data flow within the GPU and expands the number of GPU cores, reaching up to 16 cores for enhanced performance.

The Arm 5th Gen GPU architecture is the most efficient GPU architecture Arm has ever created, designed with CPU and system architecture in mind. It redefines parts of the graphics pipeline to significantly reduce memory bandwidth, thus improving total system efficiency and power.

Technical reference: It solves the bandwidth problem of the traditional model because the fragment shader reads a small block each time and puts it on the chip. It does not need to read the memory frequently until the final operation is completed and then writes it to the memory. You can even further reduce memory reads and writes by compressing tiles. In addition, when some areas of the image are fixed, the function can be called to determine whether the tiles are the same to reduce repeated rendering.

Vulnerability details: A local non-privileged user can make improper GPU memory processing operations. On Armv8.0 cores, there are certain combinations of the Linux Kernel and Mali GPU kernel driver configurations that would allow the GPU operations to affect the userspace memory of other processes.

Ref: Arm did not provide details. Is the senario on attached diagram similar to this CVE?

Resolution: This issue is fixed in Bifrost, Valhall and Arm 5th Gen GPU Architecture Kernel Driver r48p0. Users are recommended to upgrade if they are impacted by this issue.

Official announcement: Please refer to the link for details –

Starting from CVE-2024-34476, other design flaws have also been found, please use non-vulnerable Open5GS versions for development. (4-May-2024)

Preface: The two prerequisites for running Open5GS are the Open5GS core and MongoDB. The MongoDB, a document-based database, for user equipment registration. MongoDB uses some weird special processor instruction, which is not provided in intel Celeron processor.

Background: The Access and Mobility Management Function (AMF) is one of the control plane network functions (NF) of the 5G core network (5GC). The control plane in 5G Network Architecture contains the AMF which is the first node in the control plane that connects to the gNB. And it is responsible for the access and mobility management. The SMF, that is responsible for session management.

Authentication messages are a set of NAS message involved in Athenticating UE to 5G RAN and Core Network. Mainly three NAS messages are involved : AuthenticationRequest, AuthenticationResponse. Important Information of RegistrationRequest are : Authentication Key Information.

Vulnerability details: Open5GS before 2.7.1 is vulnerable to a reachable assertion that can cause an AMF crash via NAS messages from a UE: ogs_nas_encrypt in lib/nas/common/security[.]c for pkbuf->len.

Official announcement: Please refer to the link for details –