CVE-2020-17519 is a vulnerability in Apache Flink
Published on January 5, 2021
Apache Flink directory traversal attack: reading remote files through the REST API
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.
Known Exploited Vulnerability
This Apache Flink Improper Access Control Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. Apache Flink contains an improper access control vulnerability that allows an attacker to read any file on the local filesystem of the JobManager through its REST interface.
The following remediation steps are recommended / required by June 13, 2024: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Vulnerability Analysis
CVE-2020-17519 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. This vulnerability is known to be actively exploited by threat actors in an automatable fashion. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity, and a high impact on availability.
Weakness Type
Files or Directories Accessible to External Parties
The product makes files or directories accessible to unauthorized actors, even though they should not be. Web servers, FTP servers, and similar servers may store a set of files underneath a "root" directory that is accessible to the server's users. Applications may store sensitive files underneath this root without also using access control to limit which users may request those files, if any. Alternately, an application might package multiple files or directories into an archive file (e.g., ZIP or tar), but the application might not exclude sensitive files that are underneath those directories.
Products Associated with CVE-2020-17519
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Affected Versions
Apache Software Foundation Apache Flink:- Version Apache Flink 1.11.0 to 1.11.2 is affected.
- Version 1.11.0, <= 1.11.2 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.