OXDC-ADV-2024-0003

Vulnerability from csaf_ox - Published: 2024-09-10 00:00 - Updated: 2024-09-10 00:00
Summary
OX Dovecot Pro Security Advisory OXDC-ADV-2024-0003
Severity
High
CVE-2024-23185

Very large headers can cause resource exhaustion when parsing message. The message-parser normally reads reasonably sized chunks of the message. However, when it feeds them to message-header-parser, it starts building up "full_value" buffer out of the smaller chunks. The full_value buffer has no size limit, so large headers can cause large memory usage. It doesn't matter whether it's a single long header line, or a single header split into multiple lines. This bug exists in all Dovecot versions.

7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-770 - Allocation of Resources Without Limits or Throttling
Affected products
Product Identifier Version Remediation
OX Dovecot Pro core 2.3.21
Open-Xchange GmbH / OX Dovecot Pro core
 cpe:2.3:a:open-xchange:dovecot:2.3.21:*:*:*:*:*:*:* 2.3.21
Vendor Fix
Product Identifier Version Remediation
OX Dovecot Pro core 2.3.21.1
Open-Xchange GmbH / OX Dovecot Pro core
 cpe:2.3:a:open-xchange:dovecot:2.3.21.1:*:*:*:*:*:*:* 2.3.21.1
OX Dovecot Pro core 3.0.0
Open-Xchange GmbH / OX Dovecot Pro core
 cpe:2.3:a:open-xchange:dovecot:3.0.0:*:*:*:*:*:*:* 3.0.0
Threats
Impact Incoming mails typically have some size limits set by MTA, so even largest possible header size may still fit into Dovecot's vsz_limit. So attackers probably can't DoS a victim user this way. A user could APPEND larger mails though, allowing them to DoS themselves (although maybe cause some memory issues for the backend in general).
Exploit Status No publicly available exploits are known.
References
To clipboard 

{
  "document": {
    "aggregate_severity": {
      "text": "HIGH"
    },
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "tlp": {
        "label": "GREEN",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "publisher": {
      "category": "vendor",
      "name": "Open-Xchange GmbH",
      "namespace": "https://open-xchange.com/"
    },
    "references": [
      {
        "category": "self",
        "summary": "Canonical CSAF document",
        "url": "https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2024/oxdc-adv-2024-0003.json"
      },
      {
        "category": "self",
        "summary": "Markdown representation",
        "url": "https://documentation.open-xchange.com/dovecot/security/advisories/md/2024/oxdc-adv-2024-0003.md"
      },
      {
        "category": "self",
        "summary": "HTML representation",
        "url": "https://documentation.open-xchange.com/dovecot/security/advisories/html/2024/oxdc-adv-2024-0003.html"
      },
      {
        "category": "self",
        "summary": "Plain-text representation",
        "url": "https://documentation.open-xchange.com/dovecot/security/advisories/txt/2024/oxdc-adv-2024-0003.txt"
      }
    ],
    "title": "OX Dovecot Pro Security Advisory OXDC-ADV-2024-0003",
    "tracking": {
      "current_release_date": "2024-09-10T00:00:00+00:00",
      "generator": {
        "date": "2024-09-10T14:45:00+00:00",
        "engine": {
          "name": "OX CSAF",
          "version": "1.0.0"
        }
      },
      "id": "OXDC-ADV-2024-0003",
      "initial_release_date": "2024-09-10T00:00:00+02:00",
      "revision_history": [
        {
          "date": "2024-09-10T00:00:00+02:00",
          "number": "1",
          "summary": "Initial release"
        },
        {
          "date": "2024-09-10T00:00:00+00:00",
          "number": "2",
          "summary": "Public release"
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "2.3.21",
                "product": {
                  "name": "OX Dovecot Pro core 2.3.21",
                  "product_id": "OXDC-CORE_2.3.21",
                  "product_identification_helper": {
                    "cpe": "cpe:2.3:a:open-xchange:dovecot:2.3.21:*:*:*:*:*:*:*"
                  }
                }
              },
              {
                "category": "product_version",
                "name": "2.3.21.1",
                "product": {
                  "name": "OX Dovecot Pro core 2.3.21.1",
                  "product_id": "OXDC-CORE_2.3.21.1",
                  "product_identification_helper": {
                    "cpe": "cpe:2.3:a:open-xchange:dovecot:2.3.21.1:*:*:*:*:*:*:*"
                  }
                }
              },
              {
                "category": "product_version",
                "name": "3.0.0",
                "product": {
                  "name": "OX Dovecot Pro core 3.0.0",
                  "product_id": "OXDC-CORE_3.0.0",
                  "product_identification_helper": {
                    "cpe": "cpe:2.3:a:open-xchange:dovecot:3.0.0:*:*:*:*:*:*:*"
                  }
                }
              }
            ],
            "category": "product_name",
            "name": "OX Dovecot Pro core"
          }
        ],
        "category": "vendor",
        "name": "Open-Xchange GmbH"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2024-23185",
      "cwe": {
        "id": "CWE-770",
        "name": "Allocation of Resources Without Limits or Throttling"
      },
      "discovery_date": "2024-01-31T11:55:28+01:00",
      "ids": [
        {
          "system_name": "JIRA OX Bug",
          "text": "DOV-6601"
        }
      ],
      "notes": [
        {
          "category": "description",
          "text": "Very large headers can cause resource exhaustion when parsing message. The message-parser normally reads reasonably sized chunks of the message. However, when it feeds them to message-header-parser, it starts building up \"full_value\" buffer out of the smaller chunks. The full_value buffer has no size limit, so large headers can cause large memory usage. It doesn\u0027t matter whether it\u0027s a single long header line, or a single header split into multiple lines. This bug exists in all Dovecot versions."
        }
      ],
      "product_status": {
        "first_fixed": [
          "OXDC-CORE_2.3.21.1",
          "OXDC-CORE_3.0.0"
        ],
        "last_affected": [
          "OXDC-CORE_2.3.21"
        ]
      },
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2024-08-21T08:59:54+02:00",
          "details": "One can implement restrictions on headers on MTA component preceding Dovecot.",
          "product_ids": [
            "OXDC-CORE_2.3.21"
          ]
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "OXDC-CORE_2.3.21"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Incoming mails typically have some size limits set by MTA, so even largest possible header size may still fit into Dovecot\u0027s vsz_limit. So attackers probably can\u0027t DoS a victim user this way. A user could APPEND larger mails though, allowing them to DoS themselves (although maybe cause some memory issues for the backend in general)."
        },
        {
          "category": "exploit_status",
          "details": "No publicly available exploits are known."
        }
      ],
      "title": "Message headers have no size limit when parsing"
    }
  ]
}


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