cbcvebase.
CVE-2020-17519
published 2021-01-05

CVE-2020-17519: A change introduced in Apache Flink 1.11.0 (and released in 1.11.1 and 1.11.2 as well) allows attackers to read any file on the local filesystem of the…

PriorityP190high7.5CVSS 3.1
AVNACLPRNUINSUCHINAN
KEVITWEXPLOIT
CISA Known Exploited Vulnerabilitydue 2024-06-13
Exploited in the wild
EPSS
97.86%
99.9th percentile
A change introduced in Apache Flink 1.11.0 (and released in 1.11.1 and 1.11.2 as well) allows attackers to read any file on the local filesystem of the JobManager through the REST interface of the JobManager process. Access is restricted to files accessible by the JobManager process. All users should upgrade to Flink 1.11.3 or 1.12.0 if their Flink instance(s) are exposed. The issue was fixed in commit b561010b0ee741543c3953306037f00d7a9f0801 from apache/flink:master.

Affected

3 ranges
VendorProductVersion rangeFixed in
apacheflink
apacheflink>= 1.11.0 < 1.11.31.11.3
apache_software_foundationapache_flink

Detection & IOCsextracted from sources · hover to see the quote

url/jobmanager/logs/..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252f..%252fetc%252fpasswd
path/jobmanager/logs/
bytes
..%252f (double URL-encoded directory traversal sequence)
  • Detect HTTP GET requests to the Flink JobManager REST API path '/jobmanager/logs/' containing double URL-encoded traversal sequences ('%252f') in the URI, which is the canonical exploitation pattern for this LFI.
  • Match HTTP 200 responses from the Flink JobManager REST interface whose body contains 'root:.*:0:0:' (passwd file content), indicating successful arbitrary file read exploitation.
  • The vulnerability is in the JobManager REST interface; monitor for any unauthenticated GET requests to '/jobmanager/logs/' with path traversal patterns, as the API fails to validate user-supplied log file paths.
  • ·Exploitation is limited to files readable by the JobManager OS process; attackers cannot read files outside the process's filesystem permissions.
  • ·The default traversal depth used in the Metasploit module is 12 levels; detection rules should account for variable depth values (DEPTH parameter is configurable).
  • ·Affected versions are strictly 1.11.0, 1.11.1, and 1.11.2; the fix was introduced in commit b561010b0ee741543c3953306037f00d7a9f0801 and released in Flink 1.11.3 and 1.12.0.

CVSS provenance

nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:P/I:N/A:N
vulncheck7.5HIGH
cisa7.5HIGH
vendor_apache7.5HIGH
vendor_redhat7.5HIGH
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