CVE-2020-12443

BigBlueButton before 2.2.6 allows remote attackers to read arbitrary files because the presfilename (lowercase) value can be a .pdf filename while the presFilename (mixed case) value has a ../ sequence. This can be leveraged for privilege escalation via a directory traversal to bigbluebutton.properties. NOTE: this issue exists because of an ineffective mitigation to CVE-2020-12112 in which there was an attempted fix within an NGINX configuration file, without considering that the relevant part of NGINX is case-insensitive.

CVSS v3.0 9.8 CRITICAL
CVSS v2.0 7.5 HIGH

9.8^/10

CVSS v3.0 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

7.5^/10

CVSS v2.0 : HIGH

Vector : AV:N/AC:L/Au:N/C:P/I:P/A:P

Exploitability : 10.0 / Impact : 6.4

Access Vector NETWORK

Access Complexity LOW

Authentication NONE

Confidentiality Impact PARTIAL

Integrity Impact PARTIAL

Availability Impact PARTIAL

References

Link	Resource
https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df96984b3a4c57679a463	Patch Third Party Advisory
https://github.com/mclab-hbrs/BBB-POC	Exploit Third Party Advisory

Advertisement

Configurations

Configuration 1 (hide)

cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:*

Information

Published : 2020-04-28 19:15

Updated : 2020-05-06 07:02

NVD link : CVE-2020-12443

Mitre link : CVE-2020-12443

JSON object : View

CWE

CWE-22

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Advertisement

Products Affected

bigbluebutton

bigbluebutton

{"cve": {"data_type": "CVE", "references": {"reference_data": [{"url": "https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df96984b3a4c57679a463", "name": "https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df96984b3a4c57679a463", "tags": ["Patch", "Third Party Advisory"], "refsource": "MISC"}, {"url": "https://github.com/mclab-hbrs/BBB-POC", "name": "https://github.com/mclab-hbrs/BBB-POC", "tags": ["Exploit", "Third Party Advisory"], "refsource": "MISC"}]}, "data_format": "MITRE", "description": {"description_data": [{"lang": "en", "value": "BigBlueButton before 2.2.6 allows remote attackers to read arbitrary files because the presfilename (lowercase) value can be a .pdf filename while the presFilename (mixed case) value has a ../ sequence. This can be leveraged for privilege escalation via a directory traversal to bigbluebutton.properties. NOTE: this issue exists because of an ineffective mitigation to CVE-2020-12112 in which there was an attempted fix within an NGINX configuration file, without considering that the relevant part of NGINX is case-insensitive."}]}, "problemtype": {"problemtype_data": [{"description": [{"lang": "en", "value": "CWE-22"}]}]}, "data_version": "4.0", "CVE_data_meta": {"ID": "CVE-2020-12443", "ASSIGNER": "cve@mitre.org"}}, "impact": {"baseMetricV2": {"cvssV2": {"version": "2.0", "baseScore": 7.5, "accessVector": "NETWORK", "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P", "authentication": "NONE", "integrityImpact": "PARTIAL", "accessComplexity": "LOW", "availabilityImpact": "PARTIAL", "confidentialityImpact": "PARTIAL"}, "severity": "HIGH", "acInsufInfo": false, "impactScore": 6.4, "obtainAllPrivilege": false, "exploitabilityScore": 10.0, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}, "baseMetricV3": {"cvssV3": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 3.9}}, "publishedDate": "2020-04-29T02:15Z", "configurations": {"nodes": [{"children": [], "operator": "OR", "cpe_match": [{"cpe23Uri": "cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "2.2.6"}]}], "CVE_data_version": "4.0"}, "lastModifiedDate": "2020-05-06T14:02Z"}