CVE-2023-53524

What it actually does

Integer overflow in iwl_write_to_user_buf allows a negative value to be passed as the size argument to copy_to_user when a large ssize_t count is supplied, resulting in a potential heap overflow during debugfs monitor data read operations.

Why it matters to the business

The issue affects only systems running vulnerable Linux kernel versions on wireless hardware using iwlwifi; however, the flaw is confined to a read-only debugfs interface accessible solely by the file owner, producing no material operational or security risk for organizations.

How an attack unfolds

An attacker with local access and the ability to open the 0400 debugfs file iwl_dbgfs_monitor_data_read would supply SIZE_MAX as the count parameter to trigger the overflow during the subsequent copy_to_user call; no publicly known threat actors have leveraged this path.

How to fix it

Upgrade to a fixed kernel version such as Debian linux 5.10.46-1 or the upstream commit 0ad8dd870aa187d0c21d032bb2c6433559075eec; restrict debugfs access further if custom policies are in use.

How to confirm the fix worked

Confirm the running kernel version matches or exceeds the listed fixed versions for the distribution; verify that the iwl_dbgfs_monitor_data_read function no longer contains the unchecked integer cast from ssize_t to int.

Typical attack path

1. Obtain local access to a system running a vulnerable kernel with iwlwifi hardware
2. Locate and open the specific 0400 debugfs monitor data file
3. Supply SIZE_MAX to the count parameter of the read operation
4. Trigger the integer overflow leading to an oversized copy_to_user call

How to detect it

Review kernel logs and audit records for any access attempts to iwlwifi debugfs monitor files; look for unusual large read sizes or copy_to_user failures originating from the iwl_dbgfs path in crash or audit logs.

What your security team should do

• Prioritize kernel upgrades on any systems still running versions prior to the listed fixes
• Audit debugfs mount options and file permissions across fleets to ensure 0400 remains enforced
• Monitor EPSS and KEV updates for any change in exploit maturity despite current low scores