CVE-2023-52933 : Chi tiết

CVE-2023-52933

5.5
/
Trung bình
0.01%V4
2025-03-27
17h15 +00:00
Local
2025-10-28
18h29 +00:00
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Quản lý thông báo

Mô tả CVE

In the Linux kernel, the following vulnerability has been resolved: Squashfs: fix handling and sanity checking of xattr_ids count A Sysbot [1] corrupted filesystem exposes two flaws in the handling and sanity checking of the xattr_ids count in the filesystem. Both of these flaws cause computation overflow due to incorrect typing. In the corrupted filesystem the xattr_ids value is 4294967071, which stored in a signed variable becomes the negative number -225. Flaw 1 (64-bit systems only): The signed integer xattr_ids variable causes sign extension. This causes variable overflow in the SQUASHFS_XATTR_*(A) macros. The variable is first multiplied by sizeof(struct squashfs_xattr_id) where the type of the sizeof operator is "unsigned long". On a 64-bit system this is 64-bits in size, and causes the negative number to be sign extended and widened to 64-bits and then become unsigned. This produces the very large number 18446744073709548016 or 2^64 - 3600. This number when rounded up by SQUASHFS_METADATA_SIZE - 1 (8191 bytes) and divided by SQUASHFS_METADATA_SIZE overflows and produces a length of 0 (stored in len). Flaw 2 (32-bit systems only): On a 32-bit system the integer variable is not widened by the unsigned long type of the sizeof operator (32-bits), and the signedness of the variable has no effect due it always being treated as unsigned. The above corrupted xattr_ids value of 4294967071, when multiplied overflows and produces the number 4294963696 or 2^32 - 3400. This number when rounded up by SQUASHFS_METADATA_SIZE - 1 (8191 bytes) and divided by SQUASHFS_METADATA_SIZE overflows again and produces a length of 0. The effect of the 0 length computation: In conjunction with the corrupted xattr_ids field, the filesystem also has a corrupted xattr_table_start value, where it matches the end of filesystem value of 850. This causes the following sanity check code to fail because the incorrectly computed len of 0 matches the incorrect size of the table reported by the superblock (0 bytes). len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids); indexes = SQUASHFS_XATTR_BLOCKS(*xattr_ids); /* * The computed size of the index table (len bytes) should exactly * match the table start and end points */ start = table_start + sizeof(*id_table); end = msblk->bytes_used; if (len != (end - start)) return ERR_PTR(-EINVAL); Changing the xattr_ids variable to be "usigned int" fixes the flaw on a 64-bit system. This relies on the fact the computation is widened by the unsigned long type of the sizeof operator. Casting the variable to u64 in the above macro fixes this flaw on a 32-bit system. It also means 64-bit systems do not implicitly rely on the type of the sizeof operator to widen the computation. [1] https://lore.kernel.org/lkml/000000000000cd44f005f1a0f17f@google.com/

Thông tin CVE

Điểm yếu liên quan

CWE-ID Tên điểm yếu Nguồn
CWE-190 Integer Overflow or Wraparound
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

Số liệu

Số liệu Điểm Mức độ nghiêm trọng CVSS Vector Nguồn
V3.1 5.5 MEDIUM CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Local

The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities.

Attack Complexity

This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

Low

The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.

User Interaction

This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Unchanged

An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

None

There is no loss of confidentiality within the impacted component.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

None

There is no loss of integrity within the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

nvd@nist.gov

EPSS

EPSS là mô hình tính điểm dự đoán khả năng một lỗ hổng bị khai thác.

Điểm EPSS

Mô hình EPSS tạo ra điểm xác suất từ 0 đến 1 (0 đến 100%). Điểm càng cao, xác suất một lỗ hổng bị khai thác càng lớn.

Phân vị EPSS

Phân vị được dùng để xếp hạng CVE theo điểm EPSS. Ví dụ, một CVE ở phân vị thứ 95 theo điểm EPSS có nhiều khả năng bị khai thác hơn 95% CVE khác. Do đó, phân vị được dùng để so sánh điểm EPSS của một CVE với các CVE khác.

Sản phẩm được đề cập

Cấu hình 0

Linux>>Linux_kernel >> Version Từ (bao gồm) 4.4.258 Đến (không bao gồm) 4.5

Linux>>Linux_kernel >> Version Từ (bao gồm) 4.9.258 Đến (không bao gồm) 4.10

Linux>>Linux_kernel >> Version Từ (bao gồm) 4.14.222 Đến (không bao gồm) 4.14.306

Linux>>Linux_kernel >> Version Từ (bao gồm) 4.19.176 Đến (không bao gồm) 4.19.273

Linux>>Linux_kernel >> Version Từ (bao gồm) 5.4.98 Đến (không bao gồm) 5.4.232

Linux>>Linux_kernel >> Version Từ (bao gồm) 5.10.16 Đến (không bao gồm) 5.10.168

Linux>>Linux_kernel >> Version Từ (bao gồm) 5.11.1 Đến (không bao gồm) 5.15.93

Linux>>Linux_kernel >> Version Từ (bao gồm) 5.16 Đến (không bao gồm) 6.1.11

Linux>>Linux_kernel >> Version 5.11

Linux>>Linux_kernel >> Version 6.2

Linux>>Linux_kernel >> Version 6.2

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Linux>>Linux_kernel >> Version 6.2

Linux>>Linux_kernel >> Version 6.2

Linux>>Linux_kernel >> Version 6.2

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