# What is CVE-2023-43632? > CVE-2023-43632 is a critical-severity flaw (CVSS 9.9) in Edge Virtualization Engine from Linuxfoundation, published on 21 September 2023. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 0.7%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2023-43632 ## At a glance - **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. - **Precursor Intelligence risk score:** 54 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** Critical (CVSS 9.9 out of 10) - **Known to be exploited:** No, not on the list of flaws known to be exploited today - **Chance of use in the next 30 days:** 0.7% (latest exploit-likelihood forecast) - **Published:** 21 September 2023 - **Record last updated:** 28 September 2023 - **Main product:** Edge Virtualization Engine from Linuxfoundation - **Affected products:** 1 ## What is CVE-2023-43632? In plain terms It can be attacked from anywhere on the internet with an ordinary user account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline. ### The official description As noted in the “VTPM.md” file in the eve documentation, “VTPM is a server listening on port 8877 in EVE, exposing limited functionality of the TPM to the clients. VTPM allows clients to execute tpm2-tools binaries from a list of hardcoded options” The communication with this server is done using protobuf, and the data is comprised of 2 parts: 1. Header 2. Data When a connection is made, the server is waiting for 4 bytes of data, which will be the header, and these 4 bytes would be parsed as uint32 size of the actual data to come. Then, in the function “handleRequest” this size is then used in order to allocate a payload on the stack for the incoming data. As this payload is allocated on the stack, this will allow overflowing the stack size allocated for the relevant process with freely controlled data. * An attacker can crash the system. * An attacker can gain control over the system, specifically on the “vtpm_server” process which has very high privileges. ### What kind of flaw is it? - CWE-770: Allocation of Resources Without Limits or Throttling - CWE-789: Memory Allocation with Excessive Size Value ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Easy: no special conditions - Login needed first: An ordinary user account - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can read data, change data and take it offline Severity vector: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H` ## Is CVE-2023-43632 being exploited? Not that we know of It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.7%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 0.7%, 0.7%, 0.7%, 0.7%, 0.7%, 0.7%, 0.7%. ### Timeline - 21 September 2023: Published - 28 September 2023: Record last updated ### How Precursor Intelligence ranks it CVE-2023-43632 scores **54 out of 100 (Medium)**, with the action "Plan remediation". Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less: - Evidence it is being exploited: biggest factor - How severe it is: strong factor - How widely exposed it is: key context - Real threat activity around it: key context 85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it. ## Who is affected by CVE-2023-43632? The published record lists 1 product. Versions are as published: "3.0.0 to before 9.5.0" means from 3.0.0 up to, but not including, 9.5.0. - [Edge Virtualization Engine](https://www.precursorintelligence.com/product/linuxfoundation/edge_virtualization_engine) by [Linuxfoundation](https://www.precursorintelligence.com/vendors/linuxfoundation) (Operating system): 3.0.0 to before 9.5.0 ## How do I fix CVE-2023-43632? 1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list. 2. **Apply the vendor’s fix.** Install the latest update from the vendor. The references list where the vendor has published details. 3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in. 4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood. ### References - [asrg.io](https://asrg.io/security-advisories/cve-2023-43632/) ## Questions ### What is CVE-2023-43632? CVE-2023-43632 is a critical-severity flaw in Edge Virtualization Engine from Linuxfoundation, published on 21 September 2023. It can be attacked from anywhere on the internet with an ordinary user account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline. ### How serious is CVE-2023-43632? It scores 9.9 out of 10 on the CVSS severity scale, which is critical. Our risk score for CVE-2023-43632 is 54 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. ### Is CVE-2023-43632 being exploited? It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.7%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2023-43632 affect? For Edge Virtualization Engine from Linuxfoundation: 3.0.0 to before 9.5.0. ### How do I fix CVE-2023-43632? Install the update the vendor names in its advisory. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2023-43632 affect you? 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