CVE-2021-31800: Impacket Path Traversal Vulnerability
CRITICALCVE-2021-31800 is a CRITICAL (CVSS 9.8) path traversal vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting Impacket libraries in the PyPI ecosystem. The issue involves path traversal in impacket. Remediation is available by upgrading affected packages to version 0.9.23.
CVE-2021-31800 at a Glance
Security Impact
CVSS: 9.8
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
How to Fix CVE-2021-31800
To remediate this vulnerability, upgrade all affected Impacket dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
pip install impacket>=0.9.23Run the following command in your project directory to verify that all resolved dependencies use the patched release:
pip show impacketHow to Check if You Are Affected
To determine whether your Python environment is affected by CVE-2021-31800, inspect your installed packages using pip:
pip show impacketAnalyze the terminal output to locate any version of Impacket in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.9.23), your application is affected.
Note: The pip show impacket command checks currently installed packages in your active Python environment.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In Impacket, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2021-31800 Affected Impacket Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
impacket
|
PyPI |
< 0.9.23
|
0.9.23
|
References
Frequently Asked Questions
What is CVE-2021-31800?
Which Impacket versions are affected?
What version fixes CVE-2021-31800?
Is impacket affected?
What is the CVSS score of CVE-2021-31800?
What CWE is associated with CVE-2021-31800?
How can I check PyPI dependencies for CVE-2021-31800?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-mj63-64x7-57xf",
"modified" : "2024-09-23T17:06:06Z",
"published" : "2021-06-18T18:43:14Z",
"aliases" : [ "CVE-2021-31800" ],
"summary" : "Path traversal in impacket",
"details" : "Multiple path traversal vulnerabilities exist in smbserver.py in Impacket before 0.9.23. An attacker that connects to a running smbserver instance can list and write to arbitrary files via ../ directory traversal. This could potentially be abused to achieve arbitrary code execution by replacing /etc/shadow or an SSH authorized key.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
}, {
"type" : "CVSS_V4",
"score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "PyPI",
"name" : "impacket"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "0.9.23"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-31800"
}, {
"type" : "WEB",
"url" : "https://github.com/SecureAuthCorp/impacket/commit/49c643bf66620646884ed141c94e5fdd85bcdd2f"
}, {
"type" : "WEB",
"url" : "https://github.com/SecureAuthCorp/impacket/commit/99bd29e3995c254e2d6f6c2e3454e4271665955a"
}, {
"type" : "WEB",
"url" : "https://github.com/SecureAuthCorp/impacket/blob/cb6d43a677c338db930bc4e9161620832c1ec624/impacket/smbserver.py#L2008"
}, {
"type" : "WEB",
"url" : "https://github.com/SecureAuthCorp/impacket/blob/cb6d43a677c338db930bc4e9161620832c1ec624/impacket/smbserver.py#L2958"
}, {
"type" : "WEB",
"url" : "https://github.com/SecureAuthCorp/impacket/blob/cb6d43a677c338db930bc4e9161620832c1ec624/impacket/smbserver.py#L3485"
}, {
"type" : "WEB",
"url" : "https://github.com/SecureAuthCorp/impacket/blob/cb6d43a677c338db930bc4e9161620832c1ec624/impacket/smbserver.py#L876"
}, {
"type" : "WEB",
"url" : "https://github.com/SecureAuthCorp/impacket/releases"
}, {
"type" : "WEB",
"url" : "https://github.com/SecureAuthCorp/impacket/releases/tag/impacket_0_9_23"
}, {
"type" : "ADVISORY",
"url" : "https://github.com/advisories/GHSA-mj63-64x7-57xf"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/fortra/impacket"
}, {
"type" : "WEB",
"url" : "https://github.com/pypa/advisory-database/tree/main/vulns/impacket/PYSEC-2021-17.yaml"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IPXDPWCAPVX3UWYZ3N2T5OLBSBBUHJP6"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/KRV2C5DATXBHG6TF6CEEX54KZ75THQS3"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UF56LYB27LHEIFJTFHU3M75NMNNK2SCG"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-22" ],
"severity" : "CRITICAL",
"github_reviewed" : true,
"github_reviewed_at" : "2021-05-19T20:42:46Z",
"nvd_published_at" : "2021-05-05T11:15:00Z"
}
}