Vulnerability-Lookup

BDU:2022-06878 (CVE-2020-28935)

Vulnerability from fstec – Published: 2022-11-22 – Updated: 2024-09-16 – View on bdu.fstec.ru Fixed

Title

Уязвимость DNS-серверов NSD и Unbound, связанная с неверным определением символических ссылок перед доступом к файлу, позволяющая нарушителю вызвать отказ в обслуживании

Summary

Уязвимость DNS-серверов NSD и Unbound связана с неверным определением символических ссылок перед доступом к файлу. Эксплуатация уязвимости позволяет нарушителю вызвать отказ в обслуживании

Severity

4.6 (Medium) CVSS 2.0


                      
                        AV:L/AC:L/Au:S/C:N/I:N/A:C

5.5 (Medium) CVSS 3.0


                      
                        CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Class

Code vulnerability

Status

Confirmed by the vendor

Exploitation

Data structure manipulation

Incidents

Being clarified

Remediation

Software update

CWE

CWE-59 - Неверное определение ссылки перед доступом к файлу

Aliases

CVE-2020-28935

References

10 references

URL
https://github.com/NLnetLabs/nsd/commit/a4caec3137a1bc9eca05d38d66e2bce572ca9bd3
https://github.com/NLnetLabs/unbound/commit/ad387832979b6ce4c93f64fe706301cd7d034e87
https://github.com/NLnetLabs/unbound/issues/303
https://nvd.nist.gov/vuln/detail/CVE-2020-28935
https://security-tracker.debian.org/tracker/CVE-2020-28935
https://wiki.astralinux.ru/astra-linux-se17-bulletin-2022-1110SE17
https://www.nlnetlabs.nl/downloads/nsd/CVE-2020-28935.txt
https://wiki.astralinux.ru/astra-linux-se47-bulletin-2022-1121SE47
https://поддержка.нппкт.рф/bin/view/ОСнова/Обновления/2.4.2/
https://altsp.su/obnovleniya-bezopasnosti/

Impacted products

6 products from 5 vendors

Vendors

Сообщество свободного программного обеспечения, ООО «РусБИТех-Астра», АО «ИВК», АО «НППКТ», Stichting NLnet Labs

Products

Debian GNU/Linux, Astra Linux Special Edition (запись в едином реестре российских программ №369), Альт 8 СП (запись в едином реестре российских программ №4305), ОСОН ОСнова Оnyx (запись в едином реестре российских программ №5913), NSD, Unbound

Versions

10 (Debian GNU/Linux), 11 (Debian GNU/Linux), 1.7 (Astra Linux Special Edition), - (Альт 8 СП), 4.7 (Astra Linux Special Edition), до 2.4.2 (ОСОН ОСнова Оnyx), до 4.3.4 (NSD), до 1.13.0 (Unbound)

Product types

Operating system, Network device, Network software, Network appliance software

Platforms

Сообщество свободного программного обеспечения Debian GNU/Linux 10, Сообщество свободного программного обеспечения Debian GNU/Linux 11, ООО «РусБИТех-Астра» Astra Linux Special Edition 1.7 (запись в едином реестре российских программ №369), АО «ИВК» Альт 8 СП - (запись в едином реестре российских программ №4305), ООО «РусБИТех-Астра» Astra Linux Special Edition 4.7 ARM (запись в едином реестре российских программ №369), АО «НППКТ» ОСОН ОСнова Оnyx до 2.4.2 (запись в едином реестре российских программ №5913)

Mitigations

Для NSD: использование рекомендаций производителя: https://www.nlnetlabs.nl/downloads/nsd/CVE-2020-28935.txt Для Unbound: использование рекомендаций производителя: https://www.nlnetlabs.nl/downloads/nsd/CVE-2020-28935.txt Для ОС Astra Linux: использование рекомендаций производителя: https://wiki.astralinux.ru/astra-linux-se17-bulletin-2022-1110SE17 Для Astra Linux Special Edition 4.7: https://wiki.astralinux.ru/astra-linux-se47-bulletin-2022-1121SE47 Для ОСОН ОСнова Оnyx: Обновление программного обеспечения unbound до версии 1.13.1-1~bpo10+1 Для ОС Альт 8 СП: установка обновления из публичного репозитория программного средства

JSON

To clipboard

{
  "CVSS 2.0": "AV:L/AC:L/Au:S/C:N/I:N/A:C",
  "CVSS 3.0": "AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "CVSS 4.0": null,
  "remediation_\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": null,
  "remediation_\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435": null,
  "\u0412\u0435\u043d\u0434\u043e\u0440 \u041f\u041e": "\u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f, \u041e\u041e\u041e \u00ab\u0420\u0443\u0441\u0411\u0418\u0422\u0435\u0445-\u0410\u0441\u0442\u0440\u0430\u00bb, \u0410\u041e \u00ab\u0418\u0412\u041a\u00bb, \u0410\u041e \u00ab\u041d\u041f\u041f\u041a\u0422\u00bb, Stichting NLnet Labs",
  "\u0412\u0435\u0440\u0441\u0438\u044f \u041f\u041e": "10 (Debian GNU/Linux), 11 (Debian GNU/Linux), 1.7 (Astra Linux Special Edition), - (\u0410\u043b\u044c\u0442 8 \u0421\u041f), 4.7 (Astra Linux Special Edition), \u0434\u043e 2.4.2 (\u041e\u0421\u041e\u041d \u041e\u0421\u043d\u043e\u0432\u0430 \u041enyx), \u0434\u043e 4.3.4 (NSD), \u0434\u043e 1.13.0 (Unbound)",
  "\u0412\u043e\u0437\u043c\u043e\u0436\u043d\u044b\u0435 \u043c\u0435\u0440\u044b \u043f\u043e \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044e": "\u0414\u043b\u044f NSD:\n\u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u044f: https://www.nlnetlabs.nl/downloads/nsd/CVE-2020-28935.txt\n\n\u0414\u043b\u044f Unbound:\n\u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u044f: https://www.nlnetlabs.nl/downloads/nsd/CVE-2020-28935.txt\n\n\u0414\u043b\u044f \u041e\u0421 Astra Linux:\n\u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u044f: https://wiki.astralinux.ru/astra-linux-se17-bulletin-2022-1110SE17\n\n\u0414\u043b\u044f Astra Linux Special Edition 4.7: https://wiki.astralinux.ru/astra-linux-se47-bulletin-2022-1121SE47\n\n\u0414\u043b\u044f \u041e\u0421\u041e\u041d \u041e\u0421\u043d\u043e\u0432\u0430 \u041enyx:\n\u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0435 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f unbound \u0434\u043e \u0432\u0435\u0440\u0441\u0438\u0438 1.13.1-1~bpo10+1\n\n\u0414\u043b\u044f \u041e\u0421 \u0410\u043b\u044c\u0442 8 \u0421\u041f: \u0443\u0441\u0442\u0430\u043d\u043e\u0432\u043a\u0430 \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f \u0438\u0437 \u043f\u0443\u0431\u043b\u0438\u0447\u043d\u043e\u0433\u043e \u0440\u0435\u043f\u043e\u0437\u0438\u0442\u043e\u0440\u0438\u044f \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u0441\u0440\u0435\u0434\u0441\u0442\u0432\u0430",
  "\u0414\u0430\u0442\u0430 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0438\u044f": "09.11.2020",
  "\u0414\u0430\u0442\u0430 \u043f\u043e\u0441\u043b\u0435\u0434\u043d\u0435\u0433\u043e \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f": "16.09.2024",
  "\u0414\u0430\u0442\u0430 \u043f\u0443\u0431\u043b\u0438\u043a\u0430\u0446\u0438\u0438": "22.11.2022",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": "BDU:2022-06878",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440\u044b \u0434\u0440\u0443\u0433\u0438\u0445 \u0441\u0438\u0441\u0442\u0435\u043c \u043e\u043f\u0438\u0441\u0430\u043d\u0438\u0439 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "CVE-2020-28935",
  "\u0418\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0430",
  "\u041a\u043b\u0430\u0441\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043a\u043e\u0434\u0430",
  "\u041d\u0430\u0437\u0432\u0430\u043d\u0438\u0435 \u041f\u041e": "Debian GNU/Linux, Astra Linux Special Edition (\u0437\u0430\u043f\u0438\u0441\u044c \u0432 \u0435\u0434\u0438\u043d\u043e\u043c \u0440\u0435\u0435\u0441\u0442\u0440\u0435 \u0440\u043e\u0441\u0441\u0438\u0439\u0441\u043a\u0438\u0445 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c \u2116369), \u0410\u043b\u044c\u0442 8 \u0421\u041f (\u0437\u0430\u043f\u0438\u0441\u044c \u0432 \u0435\u0434\u0438\u043d\u043e\u043c \u0440\u0435\u0435\u0441\u0442\u0440\u0435 \u0440\u043e\u0441\u0441\u0438\u0439\u0441\u043a\u0438\u0445 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c \u21164305), \u041e\u0421\u041e\u041d \u041e\u0421\u043d\u043e\u0432\u0430 \u041enyx (\u0437\u0430\u043f\u0438\u0441\u044c \u0432 \u0435\u0434\u0438\u043d\u043e\u043c \u0440\u0435\u0435\u0441\u0442\u0440\u0435 \u0440\u043e\u0441\u0441\u0438\u0439\u0441\u043a\u0438\u0445 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c \u21165913), NSD, Unbound",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u041e\u0421 \u0438 \u0442\u0438\u043f \u0430\u043f\u043f\u0430\u0440\u0430\u0442\u043d\u043e\u0439 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u044b": "\u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Debian GNU/Linux 10 , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Debian GNU/Linux 11 , \u041e\u041e\u041e \u00ab\u0420\u0443\u0441\u0411\u0418\u0422\u0435\u0445-\u0410\u0441\u0442\u0440\u0430\u00bb Astra Linux Special Edition 1.7  (\u0437\u0430\u043f\u0438\u0441\u044c \u0432 \u0435\u0434\u0438\u043d\u043e\u043c \u0440\u0435\u0435\u0441\u0442\u0440\u0435 \u0440\u043e\u0441\u0441\u0438\u0439\u0441\u043a\u0438\u0445 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c \u2116369), \u0410\u041e \u00ab\u0418\u0412\u041a\u00bb \u0410\u043b\u044c\u0442 8 \u0421\u041f -  (\u0437\u0430\u043f\u0438\u0441\u044c \u0432 \u0435\u0434\u0438\u043d\u043e\u043c \u0440\u0435\u0435\u0441\u0442\u0440\u0435 \u0440\u043e\u0441\u0441\u0438\u0439\u0441\u043a\u0438\u0445 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c \u21164305), \u041e\u041e\u041e \u00ab\u0420\u0443\u0441\u0411\u0418\u0422\u0435\u0445-\u0410\u0441\u0442\u0440\u0430\u00bb Astra Linux Special Edition 4.7 ARM (\u0437\u0430\u043f\u0438\u0441\u044c \u0432 \u0435\u0434\u0438\u043d\u043e\u043c \u0440\u0435\u0435\u0441\u0442\u0440\u0435 \u0440\u043e\u0441\u0441\u0438\u0439\u0441\u043a\u0438\u0445 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c \u2116369), \u0410\u041e \u00ab\u041d\u041f\u041f\u041a\u0422\u00bb \u041e\u0421\u041e\u041d \u041e\u0421\u043d\u043e\u0432\u0430 \u041enyx \u0434\u043e 2.4.2  (\u0437\u0430\u043f\u0438\u0441\u044c \u0432 \u0435\u0434\u0438\u043d\u043e\u043c \u0440\u0435\u0435\u0441\u0442\u0440\u0435 \u0440\u043e\u0441\u0441\u0438\u0439\u0441\u043a\u0438\u0445 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c \u21165913)",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c DNS-\u0441\u0435\u0440\u0432\u0435\u0440\u043e\u0432 NSD \u0438 Unbound, \u0441\u0432\u044f\u0437\u0430\u043d\u043d\u0430\u044f \u0441 \u043d\u0435\u0432\u0435\u0440\u043d\u044b\u043c \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0435\u043d\u0438\u0435\u043c \u0441\u0438\u043c\u0432\u043e\u043b\u0438\u0447\u0435\u0441\u043a\u0438\u0445 \u0441\u0441\u044b\u043b\u043e\u043a \u043f\u0435\u0440\u0435\u0434 \u0434\u043e\u0441\u0442\u0443\u043f\u043e\u043c \u043a \u0444\u0430\u0439\u043b\u0443, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u0432\u044b\u0437\u0432\u0430\u0442\u044c \u043e\u0442\u043a\u0430\u0437 \u0432 \u043e\u0431\u0441\u043b\u0443\u0436\u0438\u0432\u0430\u043d\u0438\u0438",
  "\u041d\u0430\u043b\u0438\u0447\u0438\u0435 \u044d\u043a\u0441\u043f\u043b\u043e\u0439\u0442\u0430": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "\u041d\u0435\u0432\u0435\u0440\u043d\u043e\u0435 \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0435\u043d\u0438\u0435 \u0441\u0441\u044b\u043b\u043a\u0438 \u043f\u0435\u0440\u0435\u0434 \u0434\u043e\u0441\u0442\u0443\u043f\u043e\u043c \u043a \u0444\u0430\u0439\u043b\u0443 (CWE-59)",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c DNS-\u0441\u0435\u0440\u0432\u0435\u0440\u043e\u0432 NSD \u0438 Unbound \u0441\u0432\u044f\u0437\u0430\u043d\u0430 \u0441 \u043d\u0435\u0432\u0435\u0440\u043d\u044b\u043c \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0435\u043d\u0438\u0435\u043c \u0441\u0438\u043c\u0432\u043e\u043b\u0438\u0447\u0435\u0441\u043a\u0438\u0445 \u0441\u0441\u044b\u043b\u043e\u043a \u043f\u0435\u0440\u0435\u0434 \u0434\u043e\u0441\u0442\u0443\u043f\u043e\u043c \u043a \u0444\u0430\u0439\u043b\u0443. \u042d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0435\u0442 \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u0432\u044b\u0437\u0432\u0430\u0442\u044c \u043e\u0442\u043a\u0430\u0437 \u0432 \u043e\u0431\u0441\u043b\u0443\u0436\u0438\u0432\u0430\u043d\u0438\u0438",
  "\u041f\u043e\u0441\u043b\u0435\u0434\u0441\u0442\u0432\u0438\u044f \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": null,
  "\u041f\u0440\u043e\u0447\u0430\u044f \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f": null,
  "\u0421\u0432\u044f\u0437\u044c \u0441 \u0438\u043d\u0446\u0438\u0434\u0435\u043d\u0442\u0430\u043c\u0438 \u0418\u0411": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u0421\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u0430",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044f": "\u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0435 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438": "\u041c\u0430\u043d\u0438\u043f\u0443\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435 \u0441\u0442\u0440\u0443\u043a\u0442\u0443\u0440\u0430\u043c\u0438 \u0434\u0430\u043d\u043d\u044b\u0445",
  "\u0421\u0441\u044b\u043b\u043a\u0438 \u043d\u0430 \u0438\u0441\u0442\u043e\u0447\u043d\u0438\u043a\u0438": "https://github.com/NLnetLabs/nsd/commit/a4caec3137a1bc9eca05d38d66e2bce572ca9bd3\nhttps://github.com/NLnetLabs/unbound/commit/ad387832979b6ce4c93f64fe706301cd7d034e87\nhttps://github.com/NLnetLabs/unbound/issues/303\nhttps://nvd.nist.gov/vuln/detail/CVE-2020-28935\nhttps://security-tracker.debian.org/tracker/CVE-2020-28935\nhttps://wiki.astralinux.ru/astra-linux-se17-bulletin-2022-1110SE17\nhttps://www.nlnetlabs.nl/downloads/nsd/CVE-2020-28935.txt\nhttps://wiki.astralinux.ru/astra-linux-se47-bulletin-2022-1121SE47\nhttps://\u043f\u043e\u0434\u0434\u0435\u0440\u0436\u043a\u0430.\u043d\u043f\u043f\u043a\u0442.\u0440\u0444/bin/view/\u041e\u0421\u043d\u043e\u0432\u0430/\u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f/2.4.2/\nhttps://altsp.su/obnovleniya-bezopasnosti/",
  "\u0421\u0442\u0430\u0442\u0443\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041f\u043e\u0434\u0442\u0432\u0435\u0440\u0436\u0434\u0435\u043d\u0430 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u0435\u043c",
  "\u0422\u0438\u043f \u041f\u041e": "\u041e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u0430\u044f \u0441\u0438\u0441\u0442\u0435\u043c\u0430, \u0421\u0435\u0442\u0435\u0432\u043e\u0435 \u0441\u0440\u0435\u0434\u0441\u0442\u0432\u043e, \u0421\u0435\u0442\u0435\u0432\u043e\u0435 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0435 \u0441\u0440\u0435\u0434\u0441\u0442\u0432\u043e, \u041f\u041e \u0441\u0435\u0442\u0435\u0432\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e-\u0430\u043f\u043f\u0430\u0440\u0430\u0442\u043d\u043e\u0433\u043e \u0441\u0440\u0435\u0434\u0441\u0442\u0432\u0430",
  "\u0422\u0438\u043f \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "CWE-59",
  "\u0423\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0421\u0440\u0435\u0434\u043d\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 2.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 4,6)\n\u0421\u0440\u0435\u0434\u043d\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 3.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 5,5)"
}

CVE-2020-28935 (GCVE-0-2020-28935)

Vulnerability from cvelistv5 – Published: 2020-12-07 21:46 – Updated: 2024-09-16 23:27

Title

Local symlink attack in Unbound and NSD

Summary

NLnet Labs Unbound, up to and including version 1.12.0, and NLnet Labs NSD, up to and including version 4.3.3, contain a local vulnerability that would allow for a local symlink attack. When writing the PID file, Unbound and NSD create the file if it is not there, or open an existing file for writing. In case the file was already present, they would follow symlinks if the file happened to be a symlink instead of a regular file. An additional chown of the file would then take place after it was written, making the user Unbound/NSD is supposed to run as the new owner of the file. If an attacker has local access to the user Unbound/NSD runs as, she could create a symlink in place of the PID file pointing to a file that she would like to erase. If then Unbound/NSD is killed and the PID file is not cleared, upon restarting with root privileges, Unbound/NSD will rewrite any file pointed at by the symlink. This is a local vulnerability that could create a Denial of Service of the system Unbound/NSD is running on. It requires an attacker having access to the limited permission user Unbound/NSD runs as and point through the symlink to a critical file on the system.

Severity

No CVSS data available.

CWE

CWE-59 - Improper Link Resolution Before File Access ('Link Following')

Assigner

NLnet Labs

References

5 references

URL	Tags
https://www.nlnetlabs.nl/downloads/unbound/CVE-20…
https://www.nlnetlabs.nl/downloads/nsd/CVE-2020-2…
https://security.gentoo.org/glsa/202101-38	vendor-advisory
https://lists.debian.org/debian-lts-announce/2021…	mailing-list
https://lists.debian.org/debian-lts-announce/2023…	mailing-list

Impacted products

2 products

Vendor	Product	Version
NLnet Labs	Unbound	Affected: <= 1.12.0
NLnet Labs	NSD	Affected: <= 4.3.3

Date Public

2020-12-01 00:00

Credits

We would like to thank Mason Loring Bliss for bringing the issue to our attention.

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T16:48:00.719Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2020-28935.txt"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://www.nlnetlabs.nl/downloads/nsd/CVE-2020-28935.txt"
          },
          {
            "name": "GLSA-202101-38",
            "tags": [
              "vendor-advisory",
              "x_transferred"
            ],
            "url": "https://security.gentoo.org/glsa/202101-38"
          },
          {
            "name": "[debian-lts-announce] 20210212 [SECURITY] [DLA 2556-1] unbound1.9 security update",
            "tags": [
              "mailing-list",
              "x_transferred"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2021/02/msg00017.html"
          },
          {
            "name": "[debian-lts-announce] 20230329 [SECURITY] [DLA 3371-1] unbound security update",
            "tags": [
              "mailing-list",
              "x_transferred"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2023/03/msg00024.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Unbound",
          "vendor": "NLnet Labs",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c= 1.12.0"
            }
          ]
        },
        {
          "product": "NSD",
          "vendor": "NLnet Labs",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c= 4.3.3"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "We would like to thank Mason Loring Bliss for bringing the issue to our attention."
        }
      ],
      "datePublic": "2020-12-01T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "NLnet Labs Unbound, up to and including version 1.12.0, and NLnet Labs NSD, up to and including version 4.3.3, contain a local vulnerability that would allow for a local symlink attack. When writing the PID file, Unbound and NSD create the file if it is not there, or open an existing file for writing. In case the file was already present, they would follow symlinks if the file happened to be a symlink instead of a regular file. An additional chown of the file would then take place after it was written, making the user Unbound/NSD is supposed to run as the new owner of the file. If an attacker has local access to the user Unbound/NSD runs as, she could create a symlink in place of the PID file pointing to a file that she would like to erase. If then Unbound/NSD is killed and the PID file is not cleared, upon restarting with root privileges, Unbound/NSD will rewrite any file pointed at by the symlink. This is a local vulnerability that could create a Denial of Service of the system Unbound/NSD is running on. It requires an attacker having access to the limited permission user Unbound/NSD runs as and point through the symlink to a critical file on the system."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-59",
              "description": "CWE-59: Improper Link Resolution Before File Access (\u0027Link Following\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2023-03-29T00:00:00.000Z",
        "orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
        "shortName": "NLnet Labs"
      },
      "references": [
        {
          "url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2020-28935.txt"
        },
        {
          "url": "https://www.nlnetlabs.nl/downloads/nsd/CVE-2020-28935.txt"
        },
        {
          "name": "GLSA-202101-38",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://security.gentoo.org/glsa/202101-38"
        },
        {
          "name": "[debian-lts-announce] 20210212 [SECURITY] [DLA 2556-1] unbound1.9 security update",
          "tags": [
            "mailing-list"
          ],
          "url": "https://lists.debian.org/debian-lts-announce/2021/02/msg00017.html"
        },
        {
          "name": "[debian-lts-announce] 20230329 [SECURITY] [DLA 3371-1] unbound security update",
          "tags": [
            "mailing-list"
          ],
          "url": "https://lists.debian.org/debian-lts-announce/2023/03/msg00024.html"
        }
      ],
      "title": "Local symlink attack in Unbound and NSD"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
    "assignerShortName": "NLnet Labs",
    "cveId": "CVE-2020-28935",
    "datePublished": "2020-12-07T21:46:47.878Z",
    "dateReserved": "2020-11-18T00:00:00.000Z",
    "dateUpdated": "2024-09-16T23:27:01.127Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

BDU:2022-06878 (CVE-2020-28935)

CVE-2020-28935 (GCVE-0-2020-28935)

Tags

Sightings

Nomenclature

Related by attack behaviour