GHSA-F7HX-FQXW-RVVJ

Vulnerability from github – Published: 2020-05-27 16:37 – Updated: 2023-01-20 22:02
VLAI
Summary
Insufficient output escaping of attachment names in PHPMailer
Details

Impact

CWE-116: Incorrect output escaping.

An attachment added like this (note the double quote within the attachment name, which is entirely valid):

$mail->addAttachment('/tmp/attachment.tmp', 'filename.html";.jpg');

Will result in a message containing these headers:

Content-Type: application/octet-stream; name="filename.html";.jpg"
Content-Disposition: attachment; filename="filename.html";.jpg"

The attachment will be named filename.html, and the trailing ";.jpg" will be ignored. Mail filters that reject .html attachments but permit .jpg attachments may be fooled by this.

Note that the MIME type itself is obtained automatically from the source filename (in this case attachment.tmp, which maps to a generic application/octet-stream type), and not the name given to the attachment (though these are the same if a separate name is not provided), though it can be set explicitly in other parameters to attachment methods.

Patches

Patched in PHPMailer 6.1.6 by escaping double quotes within the name using a backslash, as per RFC822 section 3.4.1, resulting in correctly escaped headers like this:

Content-Type: application/octet-stream; name="filename.html\";.jpg"
Content-Disposition: attachment; filename="filename.html\";.jpg"

Workarounds

Reject or filter names and filenames containing double quote (") characters before passing them to attachment functions such as addAttachment().

References

CVE-2020-13625. PHPMailer 6.1.6 release

For more information

If you have any questions or comments about this advisory: * Open an issue in the PHPMailer repo

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "phpmailer/phpmailer"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2020-13625"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-116"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2020-05-27T16:34:44Z",
    "nvd_published_at": "2020-06-08T17:15:00Z",
    "severity": "HIGH"
  },
  "details": "### Impact\nCWE-116: Incorrect output escaping.\n\nAn attachment added like this (note the double quote within the attachment name, which is entirely valid):\n\n    $mail-\u003eaddAttachment(\u0027/tmp/attachment.tmp\u0027, \u0027filename.html\";.jpg\u0027);\n\nWill result in a message containing these headers:\n\n    Content-Type: application/octet-stream; name=\"filename.html\";.jpg\"\n    Content-Disposition: attachment; filename=\"filename.html\";.jpg\"\n\nThe attachment will be named `filename.html`, and the trailing `\";.jpg\"` will be ignored. Mail filters that reject `.html` attachments but permit `.jpg` attachments may be fooled by this.\n\nNote that the MIME type itself is obtained automatically from the *source filename* (in this case `attachment.tmp`, which maps to a generic `application/octet-stream` type), and not the *name* given to the attachment (though these are the same if a separate name is not provided), though it can be set explicitly in other parameters to attachment methods.\n\n### Patches\nPatched in PHPMailer 6.1.6 by escaping double quotes within the name using a backslash, as per RFC822 section 3.4.1, resulting in correctly escaped headers like this:\n\n    Content-Type: application/octet-stream; name=\"filename.html\\\";.jpg\"\n    Content-Disposition: attachment; filename=\"filename.html\\\";.jpg\"\n\n### Workarounds\nReject or filter names and filenames containing double quote (`\"`) characters before passing them to attachment functions such as `addAttachment()`.\n\n### References\n[CVE-2020-13625](https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-13625).\n[PHPMailer 6.1.6 release](https://github.com/PHPMailer/PHPMailer/releases/tag/v6.1.6)\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [the PHPMailer repo](https://github.com/PHPMailer/PHPMailer/issues)",
  "id": "GHSA-f7hx-fqxw-rvvj",
  "modified": "2023-01-20T22:02:41Z",
  "published": "2020-05-27T16:37:02Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/PHPMailer/PHPMailer/security/advisories/GHSA-f7hx-fqxw-rvvj"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-13625"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PHPMailer/PHPMailer/commit/c2796cb1cb99d7717290b48c4e6f32cb6c60b7b3"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/PHPMailer/PHPMailer"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PHPMailer/PHPMailer/releases/tag/v6.1.6"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2020/06/msg00014.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2020/08/msg00004.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/EFM3BZABL6RUHTVMXSC7OFMP4CKWMRPJ"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SMH4TC5XTS3KZVGMSKEPPBZ2XTZCKKCX"
    },
    {
      "type": "WEB",
      "url": "https://usn.ubuntu.com/4505-1"
    },
    {
      "type": "WEB",
      "url": "http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00067.html"
    },
    {
      "type": "WEB",
      "url": "http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00085.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Insufficient output escaping of attachment names in PHPMailer"
}



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