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GLSA: GENTOO LINUX SECURITY ANNOUNCEMENT |
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|
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PACKAGE :ettercap |
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SUMMARY :Ettercap, remote root compromise |
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DATE :2002-02-14 21:42:00 |
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OVERVIEW |
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|
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As it is said on ettercap's home page "Ettercap is a multipurpose |
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sniffer/interceptor/logger for switched LAN". Due to improper use of the |
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memcpy() function, anyone can crash ettercap and execute code as root |
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user. |
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|
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Vulnerabillity has been confirmed and exploited in ettercap's version |
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0.6.3.1. Older versions maybe vulnerable too. |
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|
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|
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DETAIL |
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|
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Ettercap is composed of decoders which looks for user, passwords, |
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communities and stuff alike. |
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|
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Several decoders (mysql, irc, ...) suffer the following problem: |
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|
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memcpy(collector, payload, data_to_ettercap->datalen); |
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|
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Collector is declared as: |
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u_char collector[MAX_DATA]; |
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|
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Where MAX_DATA is: |
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|
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#define MAX_DATA 2000 |
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|
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Datalen is the data (after TCP/UDP header) length read from the interface. |
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So on interfaces where MTU is higher than 2000 you can exploit ettercap. |
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Since normal ethernets have MTU:1500 this bug can not be exploited due to |
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unsupported defragmentation in ettercap, but may be crashed with a forged |
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packet (ip->tot_len > MAX_DATA). |
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|
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Here are common MTU and interface types: |
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|
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65535 Hyperchannel |
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17914 16 Mbit/sec token ring |
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8166 Token Bus (IEEE 802.4) |
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4464 4 Mbit/sec token ring (IEEE 802.5) |
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1500 Ethernet |
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1500 PPP (typical; can vary widely) |
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|
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Sample explotation could be also in loopback interfaces: MTU:16436 |
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|
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piscis:~# ettercap -NszC -i lo & |
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[1] 21887 |
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piscis:~# ./ettercap-x 0 | nc localhost 3306 |
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ettercap-0.6.3.1 xploit by Fermín J. Serna <fjserna@×××××.com> |
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Next Generation Security Technologies |
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http://www.ngsec.com |
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|
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punt! |
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piscis:~# telnet localhost 36864 |
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Trying 127.0.0.1... |
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Connected to localhost. |
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Escape character is '^]'. |
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id; |
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uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),10(wheel) |
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SOLUTION |
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|
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|
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It is recommended that all ettercap users apply the update |
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|
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Portage Auto: |
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|
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emerge rsync |
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emerge update |
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emerge update --world |
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|
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Portage by hand: |
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emerge rsync |
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emerge net-analyzer/ettercap |
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|
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Manually: |
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|
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Download the new ettercap package here and follow in file instructions: |
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http://ettercap.sourceforge.net/download/ettercap-0.6.4.tar.gz |
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|
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- -------------------------------------------------------------------------- |
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Ferry Meyndert |
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m0rpheus@g.o |
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