VDE-2025-086

Vulnerability from csaf_jumogmbhcokg - Published: 2025-11-10 11:00 - Updated: 2025-11-10 11:00
Summary
Jumo: Predictable debug-interface password in variTRON series
Severity
High
Notes
Summary: A vulnerability was identified in the variTRON password generation algorithm of the debug-interface. The PRNG is initialized with the current Unix Timestamp, thus the resulting password is predictable. With the password root-access to the UART and ssh Interface can be gained. The impact is limited, since the debug-interface has to be actively enabled by an authorized user and will be deactivated automatically after the next reboot of the device.
Impact: Unauthorized root-access to the UART and ssh Interface.
Remediation: Update the affected products to version 9.0.2.5.
Mitigation: Disable the debug-interface to prevent unauthorized root-access to the UART and ssh Interface.
CVE-2025-41731

A vulnerability was identified in the password generation algorithm when accessing the debug-interface. An unauthenticated local attacker with knowledge of the password generation timeframe might be able to brute force the password in a timely manner and thus gain root access to the device if the debug interface is still enabled.

7.4 (High)
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE-338 - Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
Vendor Fix Update the affected products to version 9.0.2.5.
Mitigation Disable the debug interface to prevent unauthorized root-access to the ssh Interface. The debug interface of the ssh is deactivated after rebooting the system.
Affected products
Product Identifier Version Remediation
Unresolved product id: CSAFPID-32001 —
Unresolved product id: CSAFPID-32002 —
Unresolved product id: CSAFPID-32003 —
Product Identifier Version Remediation
Unresolved product id: CSAFPID-31001 —
Unresolved product id: CSAFPID-31002 —
Unresolved product id: CSAFPID-31003 —
References
Acknowledgments
CERT@VDE certvde.com
To clipboard 

{
  "document": {
    "acknowledgments": [
      {
        "organization": "CERT@VDE",
        "summary": "coordination",
        "urls": [
          "https://certvde.com"
        ]
      }
    ],
    "aggregate_severity": {
      "namespace": "https://www.first.org/cvss/v3.1/specification-document#Qualitative-Severity-Rating-Scale",
      "text": "High"
    },
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-GB",
    "notes": [
      {
        "category": "summary",
        "text": "A vulnerability was identified in the variTRON password generation algorithm of the debug-interface. The PRNG is initialized with the current Unix Timestamp, thus the resulting password is predictable.\nWith the password root-access to the UART and ssh Interface can be gained.\nThe impact is limited, since the debug-interface has to be actively enabled by an authorized user and will be deactivated automatically after the next reboot of the device.",
        "title": "Summary"
      },
      {
        "category": "description",
        "text": "Unauthorized root-access to the UART and ssh Interface.",
        "title": "Impact"
      },
      {
        "category": "description",
        "text": "Update the affected products to version 9.0.2.5. ",
        "title": "Remediation"
      },
      {
        "category": "description",
        "text": "Disable the debug-interface to prevent unauthorized root-access to the UART and ssh Interface.",
        "title": "Mitigation"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "psirt@jumo.net",
      "name": "JUMO GmbH \u0026 Co. KG",
      "namespace": "https://www.jumo.de"
    },
    "references": [
      {
        "category": "external",
        "summary": "Jumo PSIRT",
        "url": "https://www.jumo.de"
      },
      {
        "category": "external",
        "summary": "CERT@VDE Security Advisories for Jumo",
        "url": "https://certvde.com/de/advisories/vendor/jumo/"
      },
      {
        "category": "self",
        "summary": "VDE-2025-086: Jumo: Predictable debug-interface password in variTRON series - HTML",
        "url": "https://certvde.com/en/advisories/VDE-2025-086"
      },
      {
        "category": "self",
        "summary": "VDE-2025-086: Jumo: Predictable debug-interface password in variTRON series - CSAF",
        "url": "https://jumo.csaf-tp.certvde.com/.well-known/csaf/white/2025/vde-2025-086.json"
      }
    ],
    "title": "Jumo: Predictable debug-interface password in variTRON series",
    "tracking": {
      "aliases": [
        "VDE-2025-086"
      ],
      "current_release_date": "2025-11-10T11:00:00.000Z",
      "generator": {
        "date": "2025-11-04T13:31:42.418Z",
        "engine": {
          "name": "Secvisogram",
          "version": "2.5.38"
        }
      },
      "id": "VDE-2025-086",
      "initial_release_date": "2025-11-10T11:00:00.000Z",
      "revision_history": [
        {
          "date": "2025-11-10T11:00:00.000Z",
          "number": "1.0.0",
          "summary": "Release version."
        }
      ],
      "status": "final",
      "version": "1.0.0"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_name",
                "name": "variTRON300",
                "product": {
                  "name": "variTRON300",
                  "product_id": "CSAFPID-11001"
                }
              },
              {
                "category": "product_name",
                "name": " variTRON500",
                "product": {
                  "name": "variTRON500",
                  "product_id": "CSAFPID-11002"
                }
              },
              {
                "category": "host_name",
                "name": "variTRON500 touch",
                "product": {
                  "name": "variTRON500 touch",
                  "product_id": "CSAFPID-11003"
                }
              }
            ],
            "category": "product_family",
            "name": "Hardware"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003c9.0.2.5. ",
                "product": {
                  "name": "Firmware \u003c9.0.2.5. ",
                  "product_id": "CSAFPID-21001"
                }
              },
              {
                "category": "product_version",
                "name": "9.0.2.5. ",
                "product": {
                  "name": "Firmware 9.0.2.5. ",
                  "product_id": "CSAFPID-22001"
                }
              }
            ],
            "category": "product_family",
            "name": "Firmware"
          }
        ],
        "category": "vendor",
        "name": "Jumo"
      }
    ],
    "product_groups": [
      {
        "group_id": "CSAFGID-0001",
        "product_ids": [
          "CSAFPID-31001",
          "CSAFPID-31002",
          "CSAFPID-31003"
        ],
        "summary": "Affected products."
      },
      {
        "group_id": "CSAFGID-0002",
        "product_ids": [
          "CSAFPID-32001",
          "CSAFPID-32002",
          "CSAFPID-32003"
        ],
        "summary": "Fixed products."
      }
    ],
    "relationships": [
      {
        "category": "installed_on",
        "full_product_name": {
          "name": "Firmware \u003c9.0.2.5.  installed on variTRON300",
          "product_id": "CSAFPID-31001"
        },
        "product_reference": "CSAFPID-21001",
        "relates_to_product_reference": "CSAFPID-11001"
      },
      {
        "category": "installed_on",
        "full_product_name": {
          "name": "Firmware \u003c9.0.2.5.  installed on variTRON500",
          "product_id": "CSAFPID-31002"
        },
        "product_reference": "CSAFPID-21001",
        "relates_to_product_reference": "CSAFPID-11002"
      },
      {
        "category": "installed_on",
        "full_product_name": {
          "name": "Firmware \u003c9.0.2.5.  installed on variTRON500 touch",
          "product_id": "CSAFPID-31003"
        },
        "product_reference": "CSAFPID-21001",
        "relates_to_product_reference": "CSAFPID-11003"
      },
      {
        "category": "installed_on",
        "full_product_name": {
          "name": "Firmware 9.0.2.5.  installed on variTRON300",
          "product_id": "CSAFPID-32001"
        },
        "product_reference": "CSAFPID-22001",
        "relates_to_product_reference": "CSAFPID-11001"
      },
      {
        "category": "installed_on",
        "full_product_name": {
          "name": "Firmware 9.0.2.5.  installed on variTRON500",
          "product_id": "CSAFPID-32002"
        },
        "product_reference": "CSAFPID-22001",
        "relates_to_product_reference": "CSAFPID-11002"
      },
      {
        "category": "installed_on",
        "full_product_name": {
          "name": "Firmware 9.0.2.5.  installed on variTRON500 touch",
          "product_id": "CSAFPID-32003"
        },
        "product_reference": "CSAFPID-22001",
        "relates_to_product_reference": "CSAFPID-11003"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2025-41731",
      "cwe": {
        "id": "CWE-338",
        "name": "Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)"
      },
      "notes": [
        {
          "category": "description",
          "text": "A vulnerability was identified in the password generation algorithm when accessing the debug-interface. An unauthenticated local attacker with knowledge of the password generation timeframe might be able to brute force the password in a timely manner and thus gain root access to the device if the debug interface is still enabled.",
          "title": "CVE Description"
        }
      ],
      "product_status": {
        "fixed": [
          "CSAFPID-32001",
          "CSAFPID-32002",
          "CSAFPID-32003"
        ],
        "known_affected": [
          "CSAFPID-31001",
          "CSAFPID-31002",
          "CSAFPID-31003"
        ]
      },
      "references": [
        {
          "category": "external",
          "summary": "Advisory: VDE-2025-015",
          "url": "https://certvde.com/en/advisories/VDE-2025-015/"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Update the affected products to version 9.0.2.5. ",
          "group_ids": [
            "CSAFGID-0001"
          ]
        },
        {
          "category": "mitigation",
          "details": "Disable the debug interface to prevent unauthorized root-access to the ssh Interface. The debug interface of the ssh is deactivated after rebooting the system.",
          "group_ids": [
            "CSAFGID-0001"
          ]
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "HIGH",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.4,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "environmentalScore": 7.4,
            "environmentalSeverity": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "temporalScore": 7.4,
            "temporalSeverity": "HIGH",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-31001",
            "CSAFPID-31002",
            "CSAFPID-31003"
          ]
        }
      ],
      "title": "Jumo: Insufficient entropy in PRNG may lead to root access"
    }
  ]
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.