CVE-2024-47535: Netty common Denial of Service Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xq3w-v528-46rv",
  "modified" : "2025-02-18T15:57:45Z",
  "published" : "2024-11-12T19:53:17Z",
  "aliases" : [ "CVE-2024-47535" ],
  "summary" : "Denial of Service attack on windows app using netty",
  "details" : "### Summary\n\nAn unsafe reading of environment file could potentially cause a denial of service in Netty.\nWhen loaded on an Windows application, Netty attemps to load a file that does not exist. If an attacker creates such a large file, the Netty application crash.\n\n\n### Details\n\nWhen the library netty is loaded in a java windows application, the library tries to identify the system environnement in which it is executed.\n\nAt this stage, Netty tries to load both `/etc/os-release` and `/usr/lib/os-release` even though it is in a Windows environment. \n\n<img width=\"364\" alt=\"1\" src=\"https://github.com/user-attachments/assets/9466b181-9394-45a3-b0e3-1dcf105def59\">\n\nIf netty finds this files, it reads them and loads them into memory.\n\nBy default :\n\n- The JVM maximum memory size is set to 1 GB,\n- A non-privileged user can create a directory at `C:\\` and create files within it.\n\n<img width=\"340\" alt=\"2\" src=\"https://github.com/user-attachments/assets/43b359a2-5871-4592-ae2b-ffc40ac76831\">\n\n<img width=\"523\" alt=\"3\" src=\"https://github.com/user-attachments/assets/ad5c6eed-451c-4513-92d5-ba0eee7715c1\">\n\nthe source code identified :\nhttps://github.com/netty/netty/blob/4.1/common/src/main/java/io/netty/util/internal/PlatformDependent.java\n\nDespite the implementation of the function `normalizeOs()` the source code not verify the OS before reading `C:\\etc\\os-release` and `C:\\usr\\lib\\os-release`.\n\n### PoC\n\nCreate a file larger than 1 GB of data in `C:\\etc\\os-release` or `C:\\usr\\lib\\os-release` on a Windows environnement and start your Netty application.\n\nTo observe what the application does with the file, the security analyst used \"Process Monitor\" from the \"Windows SysInternals\" suite. (https://learn.microsoft.com/en-us/sysinternals/)\n\n```\ncd C:\\etc\nfsutil file createnew os-release 3000000000\n```\n\n<img width=\"519\" alt=\"4\" src=\"https://github.com/user-attachments/assets/39df22a3-462b-4fd0-af9a-aa30077ec08f\">\n\n<img width=\"517\" alt=\"5\" src=\"https://github.com/user-attachments/assets/129dbd50-fc36-4da5-8eb1-582123fb528f\">\n\nThe source code used is the Netty website code example : [Echo ‐ the very basic client and server](https://netty.io/4.1/xref/io/netty/example/echo/package-summary.html).\n\nThe vulnerability was tested on the 4.1.112.Final version.\n\nThe security analyst tried the same technique for `C:\\proc\\sys\\net\\core\\somaxconn` with a lot of values to impact Netty but the only things that works is the \"larger than 1 GB file\" technique. https://github.com/netty/netty/blob/c0fdb8e9f8f256990e902fcfffbbe10754d0f3dd/common/src/main/java/io/netty/util/NetUtil.java#L186\n\n### Impact\n\nBy loading the \"file larger than 1 GB\" into the memory, the Netty library exceeds the JVM memory limit and causes a crash in the java Windows application.\n\nThis behaviour occurs 100% of the time in both Server mode and Client mode if the large file exists.\n\nClient mode :\n\n<img width=\"449\" alt=\"6\" src=\"https://github.com/user-attachments/assets/f8fe1ed0-1a42-4490-b9ed-dbc9af7804be\">\n\nServer mode :\n\n<img width=\"464\" alt=\"7\" src=\"https://github.com/user-attachments/assets/b34b42bd-4fbd-4170-b93a-d29ba87b88eb\">\n\nsomaxconn :\n\n<img width=\"532\" alt=\"8\" src=\"https://github.com/user-attachments/assets/0656b3bb-32c6-4ae2-bff7-d93babba08a3\">\n\n### Severity\n\n- Attack vector : \"Local\" because the attacker needs to be on the system where the Netty application is running.\n- Attack complexity : \"Low\" because the attacker only need to create a massive file (regardless of its contents).\n- Privileges required : \"Low\" because the attacker requires a user account to exploit the vulnerability.\n- User intercation : \"None\" because the administrator don't need to accidentally click anywhere to trigger the vulnerability. Furthermore, the exploitation works with defaults windows/AD settings.\n- Scope : \"Unchanged\" because only Netty is affected by the vulnerability.\n- Confidentiality : \"None\" because no data is exposed through exploiting the vulnerability.\n- Integrity : \"None\" because the explotation of the vulnerability does not allow editing, deleting or adding data elsewhere.\n- Availability : \"High\" because the exploitation of this vulnerability crashes the entire java application.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "io.netty:netty-common"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.1.115.Final"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.1.114.Final"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/netty/netty/security/advisories/GHSA-xq3w-v528-46rv"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2024-47535"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/netty/netty/commit/fbf7a704a82e7449b48bd0bbb679f5661c6d61a3"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/netty/netty"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-11-12T19:53:17Z",
    "nvd_published_at" : "2024-11-12T16:15:22Z"
  }
}