Vulnerability CVE-2021-21249


Published: 2021-01-15

Description:
OneDev is an all-in-one devops platform. In OneDev before version 4.0.3, there is an issue involving YAML parsing which can lead to post-auth remote code execution. In order to parse and process YAML files, OneDev uses SnakeYaml which by default (when not using `SafeConstructor`) allows the instantiation of arbitrary classes. We can leverage that to run arbitrary code by instantiating classes such as `javax.script.ScriptEngineManager` and using `URLClassLoader` to load the script engine provider, resulting in the instantiation of a user controlled class. For a full example refer to the referenced GHSA. This issue was addressed in 4.0.3 by only allowing certain known classes to be deserialized

Type:

CWE-74

CVSS2 => (AV:N/AC:L/Au:S/C:P/I:P/A:P)

CVSS Base Score
Impact Subscore
Exploitability Subscore
6.5/10
6.4/10
8/10
Exploit range
Attack complexity
Authentication
Remote
Low
Single time
Confidentiality impact
Integrity impact
Availability impact
Partial
Partial
Partial
Affected software
Onedev project -> Onedev 

 References:
https://github.com/theonedev/onedev/commit/d6fc4212b1ac1e9bbe3ce444e95f9af1e3ab8b66
https://github.com/theonedev/onedev/security/advisories/GHSA-7xhq-m2q9-6hpm

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