Azure C Shared UtilityApplication · Microsoft

CVE-2024-29195

HIGH · 8.1 CVSS v3.1 Published 2024-03-26
Fix available
A fix is available. Upgrade to after 2023-12-01 or later.
See remediation →
90/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The azure-c-shared-utility is a C library for AMQP/MQTT communication to Azure Cloud Services. This library may be used by the Azure IoT C SDK for communication between IoT Hub and IoT Hub devices. An attacker can cause an integer wraparound or under-allocation or heap buffer overflow due to vulnerabilities in parameter checking mechanism, by exploiting the buffer length parameter in Azure C SDK, which may lead to remote code execution. Requirements for RCE are 1. Compromised Azure account allowing malformed payloads to be sent to the device via IoT Hub service, 2. By passing IoT hub service max message payload limit of 128KB, and 3. Ability to overwrite code space with remote code. Fixed in commit https://github.com/Azure/azure-c-shared-utility/commit/1129147c38ac02ad974c4c701a1e01b2141b9fe2.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-120

A fixed-size buffer is filled without checking the length of the incoming data, so it overflows into neighbouring memory. This is the classic overflow attackers use to overwrite return addresses and hijack execution. The fix is strict length checks and safe, bounded string and memory functions.

General guidance for the classic buffer overflow class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Azure C Shared UtilityApplication
Affected:<= 2023-12-01

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 2023-12-01
Vendor patch github.com →
Recommended fix Moderate confidence

Any release of azure-c-shared-utility published after the 2023-12-01 release that includes commit 1129147c38ac02ad974c4c701a1e01b2141b9fe2

  1. 1. Identify all projects and dependencies that use the azure-c-shared-utility library
  2. 2. Check the current version of azure-c-shared-utility in use (versions <= 2023-12-01 are affected)
  3. 3. Update the dependency to a version released after the fix commit (1129147c38ac02ad974c4c701a1e01b2141b9fe2)
  4. 4. Rebuild and test the application to verify the vulnerability is remediated
  5. 5. If using Azure IoT C SDK, ensure it also pulls the updated azure-c-shared-utility version
  6. 6. Re-deploy the updated application to all affected devices/services

Generated from the published advisory — verify against the referenced sources before acting.

We can identify the exact fixed release, upgrade, and verify it in staging — typical engagement from $3,200. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-29195 in production — separate from our analysis above.

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What this is

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