NetSight
IP …
high8.0

CVE-2020-26217

XStream can be used for Remote Code Execution

Impact

### Impact The vulnerability may allow a remote attacker to run arbitrary shell commands only by manipulating the processed input stream. ### Patches If you rely on XStream's default blacklist of the [Security Framework](https://x-stream.github.io/security.html#framework), you will have to use at least version 1.4.14. ### Workarounds 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 1.4.13 or below who still want to use XStream default blacklist can use a workaround depending on their version in use. Users of XStream 1.4.13 can simply add two lines to XStream's setup code: ```Java xstream.denyTypes(new String[]{ "javax.imageio.ImageIO$ContainsFilter" }); xstream.denyTypes(new Class[]{ java.lang.ProcessBuilder.class }); ``` Users of XStream 1.4.12 to 1.4.7 who want to use XStream with a black list will have to setup such a list from scratch and deny at least the following types: _javax.imageio.ImageIO$ContainsFilter_, _java.beans.EventHandler_, _java.lang.ProcessBuilder_, _java.lang.Void_ and _void_. ```Java xstream.denyTypes(new String[]{ "javax.imageio.ImageIO$ContainsFilter" }); xstream.denyTypes(new Class[]{ java.lang.ProcessBuilder.class, java.beans.EventHandler.class, java.lang.ProcessBuilder.class, java.lang.Void.class, void.class }); ``` Users of XStream 1.4.6 or below can register an own converter to prevent the unmarshalling of the currently know critical types of the Java runtime. It is in fact an updated version of the workaround for CVE-2013-7285: ```Java xstream.registerConverter(new Converter() { public boolean canConvert(Class type) { return type != null && (type == java.beans.EventHandler.class || type == java.lang.ProcessBuilder.class || type == java.lang.Void.class || void.class || type.getName().equals("javax.imageio.ImageIO$ContainsFilter") || Proxy.isProxy(type)); } public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) { throw new ConversionException("Unsupported type due to security reasons."); } public void marshal(Object source, HierarchicalStreamWriter writer, MarshallingContext context) { throw new ConversionException("Unsupported type due to security reasons."); } }, XStream.PRIORITY_LOW); ``` ### Credits Chen L found and reported the issue to XStream and provided the required information to reproduce it. He was supported by Zhihong Tian and Hui Lu, both from Guangzhou University. ### References See full information about the nature of the vulnerability and the steps to reproduce it in XStream's documentation for [CVE-2020-26217](https://x-stream.github.io/CVE-2020-26217.html). ### For more information If you have any questions or comments about this advisory: * Open an issue in [XStream](https://github.com/x-stream/xstream/issues) * Contact us at [XStream Google Group](https://groups.google.com/group/xstream-user)

Affected packages

EcosystemPackageAffectedFixed in
mavencom.thoughtworks.xstream:xstream<= 1.4.131.4.14-java7

Affected products

VendorProductAffected versions
XstreamXstream
before 1.4.14
DebianDebian Linux
Versions 9.0, 10.0
NetappSnapmanager
All versions
ApacheActivemq
before 5.15.14
Version 5.16.0
OracleBanking Cash Management
Versions 14.2, 14.3, 14.5
OracleBanking Corporate Lending Process Management
Versions 14.2, 14.3, 14.5
OracleBanking Credit Facilities Process Management
Versions 14.2, 14.3, 14.5
OracleBanking Platform
Versions 2.4.0, 2.7.1, 2.9.0
OracleBanking Supply Chain Finance
Versions 14.2, 14.3, 14.5
OracleBanking Trade Finance Process Management
Versions 14.2, 14.3, 14.5
OracleBanking Virtual Account Management
Versions 14.2.0, 14.3.0, 14.5.0
OracleBusiness Activity Monitoring
Versions 11.1.1.9.0, 12.2.1.3.0, 12.2.1.4.0

Weakness classification

CWE-78

References