cbcvebase.
CVE-2020-26259
published 2020-12-16

CVE-2020-26259: XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.15, is vulnerable to an Arbitrary File Deletion on the…

PriorityP357medium6.8CVSS 3.1
AVNACHPRNUINSCCNIHAN
EPSS
82.39%
99.6th percentile
XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.15, is vulnerable to an Arbitrary File Deletion on the local host when unmarshalling. The vulnerability may allow a remote attacker to delete arbitrary know files on the host as log as the executing process has sufficient rights only by manipulating the processed input stream. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.15. The reported vulnerability does not exist running Java 15 or higher. No user is affected, who followed the recommendation to setup XStream's Security Framework with a whitelist! Anyone relying on XStream's default blacklist can immediately switch to a whilelist for the allowed types to avoid the vulnerability. Users of XStream 1.4.14 or below who still want to use XStream default blacklist can use a workaround described in more detailed in the referenced advisories.

Affected

9 ranges
VendorProductVersion rangeFixed in
apachestruts< 6.0.06.0.0
debiandebian_linux
debiandebian_linux
debianlibxstream-java< libxstream-java 1.4.15-1 (bookworm)libxstream-java 1.4.15-1 (bookworm)
fedoraprojectfedora
fedoraprojectfedora
fedoraprojectfedora
x-streamxstream< 1.4.151.4.15
xstreamxstream< 1.4.151.4.15

Detection & IOCsextracted from sources · hover to see the quote

otherjdk.nashorn.internal.objects.NativeString
urlhttps://github.com/x-stream/xstream/commit/0bcbf50126a62dfcd65f93a0da0c6d1ae92aa738
  • Detect exploitation attempts by monitoring XStream deserialization input streams for the type string 'jdk.nashorn.internal.objects.NativeString', which is part of the exploit chain.
  • Flag any XStream unmarshalling of XML payloads containing 'javax.imageio.ImageIO$ContainsFilter', 'java.lang.ProcessBuilder', 'java.beans.EventHandler', or 'java.lang.Void' type references as potentially malicious gadget chains.
  • ·The vulnerability does not affect Java 15 or higher; detection/blocking efforts are only relevant for environments running Java 14 or below.
  • ·Users who have configured XStream's Security Framework with a whitelist are not affected; detection focus should be on deployments using the default blacklist or no security framework configuration.
  • ·OpenShift Container Platform jenkins package is not affected due to JEP-200 and SECURITY-383 mitigations; do not apply XStream-specific detections to OCP jenkins deployments.

CVSS provenance

nvdv3.16.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
nvdv2.06.4MEDIUMAV:N/AC:L/Au:N/C:N/I:P/A:P
osv8.8HIGH
vendor_redhat8.8HIGH
vendor_ubuntu8.0HIGH
vendor_debian6.8MEDIUM
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