pve-manager: External Control of File Name or Path
CVE-2024-21545 is a high-severity external control of file name or path vulnerability in pve-manager from Proxmox, with a CVSS 3.1 base score of 8.2 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 7.4-19, 8.2.7 as the first without the flaw, so updating pve-manager to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.36% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update pve-manager to 7.4-19 or 8.2.7, whichever matches your release line, or a later version.
- Update libpve-storage-perl to 7.4-4 or 8.2.5, whichever matches your release line, or a later version.
- Update libpve-http-server-perl to 4.3.0 or 5.1.1, whichever matches your release line, or a later version.
- Read the advisory on forum.proxmox.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Proxmox | pve-manager | before 7.4-19; 8.0.0 up to, but not including, 8.2.7 | 7.4-19, 8.2.7 |
| Proxmox | libpve-storage-perl | before 7.4-4; 8.0.0 up to, but not including, 8.2.5 | 7.4-4, 8.2.5 |
| Proxmox | libpve-http-server-perl | 3.2-1 up to, but not including, 4.3.0; 5.0.0 up to, but not including, 5.1.1 | 4.3.0, 5.1.1 |
| Proxmox | pmg-api | before 7.3-12; 8.0.0 up to, but not including, 8.1.4 | 7.3-12, 8.1.4 |
| Proxmox | libpve-common-perl (Promox VE 8) | before 8.2.3 | 8.2.3 |
| Proxmox | libpve-common-perl (Promox Mail Gateway 8) | before 8.2.5 | 8.2.5 |
| Proxmox | mail_gateway | 6.0 up to, but not including, 7.2; 8.0 up to, but not including, 8.1-1 | 7.2, 8.1-1 |
| Proxmox | virtual_environment | 6.0 up to, but not including, 7.3; 8.0 up to, but not including, 8.2-2 | 7.3, 8.2-2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N. Scored by CNA (snyk.io).
Official description
Proxmox Virtual Environment is an open-source server management platform for enterprise virtualization. Insufficient safeguards against malicious API response values allow authenticated attackers with 'Sys.Audit' or 'VM.Monitor' privileges to download arbitrary host files via the API. When handling the result from a request handler before returning it to the user, the handle_api2_request function will check for the ‘download’ or ‘data’->’download’ objects inside the request handler call response object. If present, handle_api2_request will read a local file defined by this object and return it to the user. Two endpoints were identified which can control the object returned by a request handler sufficiently that the ’download’ object is defined and user controlled. This results in arbitrary file read. The privileges of this file read can result in full compromise of the system by various impacts such as disclosing sensitive files allowing for privileged session forgery.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: External Control of File Name or Path
The product allows user input to control or influence paths or file names that are used in filesystem operations.
How developers prevent this class of flaw
- When the set of filenames is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames, and reject all other inputs. For example, ID 1 could map to inbox.txt and ID 2 could map to profile.txt. Features such as the ESAPI AccessReferenceMap provide this capability.
- Run your code in a jail or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict all access to files within a particular directory. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More External Control of File Name or Path vulnerabilities (CWE-73)
Timeline
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other references
Recent External Control of File Name or Path vulnerabilities
- 9.4 Critical severity
- 8.1 High severity
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
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