Windows Shim OOB Read via PE Binary Load
CVE-2023-40549 Published on January 29, 2024

Shim: out-of-bounds read in verify_buffer_authenticode() malformed pe file
An out-of-bounds read flaw was found in Shim due to the lack of proper boundary verification during the load of a PE binary. This flaw allows an attacker to load a crafted PE binary, triggering the issue and crashing Shim, resulting in a denial of service.

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Vulnerability Analysis

CVE-2023-40549 can be exploited with local system access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
LOCAL
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public. 113 days later.

Weakness Type

Out-of-bounds Read

The software reads data past the end, or before the beginning, of the intended buffer. Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent read operation then produces undefined or unexpected results.


Products Associated with CVE-2023-40549

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2023-40549 are published in these products:

Red Hat Shim
 
Red Hat Enterprise Linux (RHEL)
 
Fedora Project Fedora
 
Red Hat Rhel Tus
 
Red Hat Rhel E4s
 
Red Hat Rhel Aus
 
Red Hat Rhel Eus
 

Affected Versions

Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8.2 Advanced Update Support: Red Hat Enterprise Linux 8.2 Telecommunications Update Service: Red Hat Enterprise Linux 8.2 Update Services for SAP Solutions: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.4 Telecommunications Update Service: Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions: Red Hat Enterprise Linux 8.6 Extended Update Support: Red Hat Enterprise Linux 8.8 Extended Update Support: Red Hat Enterprise Linux 8.8 Extended Update Support: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9.0 Extended Update Support: Red Hat Enterprise Linux 9.0 Extended Update Support: Red Hat Enterprise Linux 9.0 Extended Update Support: Red Hat Enterprise Linux 9.2 Extended Update Support:

Exploit Probability

EPSS
0.03%
Percentile
6.66%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.