CVE-2018-15664
Description
A flaw was discovered in the API endpoint behind the 'docker cp' command. The endpoint is vulnerable to a Time Of Check to Time Of Use (TOCTOU) vulnerability in the way it handles symbolic links inside a container. An attacker who has compromised an existing container can cause arbitrary files on the host filesystem to be read/written when an administrator tries to copy a file from/to the container.
Statement
All versions of docker prior to the fix are vulnerable to this flaw.
For clarity, in the "Affected Packages State" table, we only include OpenShift Container Platform (OCP) versions 3.7 and below because for these versions docker was shipped as part of the release. For all subsequent versions of OCP until 3.11, docker is installed from the RHEL Extras repository meaning clusters will be vulnerable to the flaw unless an updated docker package has been applied.
Red Hat Fuse provides only the Docker client library and is not affected by this vulnerability.
Mitigation
Stopping a container prior to running "docker cp" removes the TOCTOU vulnerability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | 7.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | Required | Required | N/A |
| Scope | Changed | Changed | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.0/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
NVD: CVSS:3.0/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Alter Execution Logic; Unexpected State
The attacker can gain access to otherwise unauthorized resources.
Integrity,Other
Technical Impact: Modify Application Data; Modify Files or Directories; Modify Memory; Other
Race conditions such as this kind may be employed to gain read or write access to resources which are not normally readable or writable by the user in question.
Integrity,Other
Technical Impact: Other
The resource in question, or other resources (through the corrupted one), may be changed in undesirable ways by a malicious user.
Non-Repudiation
Technical Impact: Hide Activities
If a file or other resource is written in this method, as opposed to in a valid way, logging of the activity may not occur.
Non-Repudiation,Other
Technical Impact: Other
In some cases it may be possible to delete files a malicious user might not otherwise have access to, such as log files.
Other
Technical Impact: Unexpected State
The product may perform invalid actions when the resource is in an unexpected state.
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