Increase in Office Documents Using DDE to Distribute Malware

Thursday, October 26th, 2017 | Mark Bedford | Comments Off on Increase in Office Documents Using DDE to Distribute Malware

I note from our monitoring that we have seen an uptick in tainted Office attachments or inline RTF documents that use DDE to launch malware or a downloader. The edge email gateway is now detecting the current batch of these as “Troj/DocDl-xxx” and Sophos end point is detecting these as “Torj/DocXX-xxx”.

Most people are “macro” savvy but DDE (which has been around for a long time) is a new method of propagating malware.

So if you receive an Office attachment via email and when you view it or open it you get a warning such as:

Clicking No will prevent the DDE attack from launching.

For those who click “Yes” at the first dialog then you will get another dialog warning that a command is about to be started similar to:

The “No” option is the way to prevent the attack.

If you do get documents that contain these, you should validate the senders email address and use an alternative method (not email) of contacting the sender to confirm their intent in sending the DDE documents.

Sophos Security Facebook video (no authentication required to view) https://www.facebook.com/SophosSecurity/videos/10155119823700017/

Naked Security article on the DDE attack https://nakedsecurity.sophos.com/2017/10/22/office-dde-attack-works-in-outlook-too-heres-what-to-do/

Also this Microsoft article on how to view all email messages as plain text https://support.microsoft.com/en-ca/help/831607/how-to-view-all-e-mail-messages-in-plain-text-format

 

KRACK WiFi Vulnerability

Tuesday, October 17th, 2017 | Mark Bedford | Comments Off on KRACK WiFi Vulnerability

You may have heard about a recent WiFi security problem nicknamed KRACK which was uncovered by a group of researchers early 2017. They discovered that there is a problem with the way WiFi devices negotiate their encrypted connections and this leads to some serious issues, so you should be worried but don’t panic. Your wireless password is safe as it is not disclosed (as long as it is not used elsewhere).

The issues are present in ALL devices that use the WiFi WPA protocol and include Android, Apple iOS, OSX, Windows, Linux, IoT devices. Because the vulnerability can only be exploited by an attacker in your WiFi coverage area you wont be attacked by a bad actor from the other side of the world at 3:00 am but you might by your local neighborhood hacker.

Patched or un-patched, if you use HTTPS or SSH (or anything with SSL/TLS encryption), whatever you send is secure and cannot be plainly seen or intercepted (as far as this vulnerability goes). An attacker will see that there is traffic but not the contents of the traffic. If you use a VPN (no NOT Hola or its ilk) then traffic traversing the VPN is also secure. So there maybe some privacy issues here but not confidentiality issues. In many ways this is no different than using an open WiFi network at the airport or hotel, assume that your traffic is being watched therefore sensitive information should be protected with encryption. Note for Otago VPN users, only the traffic to/from Otago is secure, other traffic may not be.

There is only one remediation at present, patch your device with the security update for this specific vulnerability when it becomes available. Vendors are currently working on patches, or have already released them. This includes lots of devices that are still working after many years of active service (the vulnerability is some 10 years old). Many older devices will never receive security updates so if you continue to use these devices you should assume that all of your traffic is being spied on and potentially altered. Time to dispose of them responsibly and upgrade them to a newer supported device.

For those wanting a more technical discussion, here is a Information Security blog article https://blogs.otago.ac.nz/infosec/2017/10/17/wpa2-krack-technical-notes/

 

Is my home Wifi network ok?

Tuesday, October 17th, 2017 | Mark Borrie | Comments Off on Is my home Wifi network ok?

What is it KRACK?

You may have heard about the latest security problem with wifi networks and be wondering what this is all about.

Yes this is a serious problem, and YES your home network is vulnerable. Every network is currently vulnerable to this new issue. More importantly, you computers, laptops, phones and other devices are also vulnerable.

What impact is there?

Potentially this impacts an extensive range of devices including Apple, Android, OpenBSD, Linux, Microsoft, smart computers, smart phones, access points, IoT devices etc. The attack cannot be executed remotely; the attacker must be within range of your wireless network ie physically near your Wi-Fi.

So what can happen? An attacker can insert themselves into your network conversations and listen to what is going back and forth. They could also potentially start changing things. If you are communicating over an encrypted link such as using https then an attacker cannot see your information. This means that your passwords will continue to stay secure.

At this time, there is no evidence that an attack tool exists in the wild but they will come sooner rather than later. Until then the attack will only be possible from a skilled attacker, however once easy-to-use tools are available the skill factor is no longer a barrier . Expect to see your neighbourhood hackers attacking your old iPhone or Android device.

What to do about it?

With this in mind you should patch all of your devices soon.

If you have an older device then the manufacturer may not release patches for this issue. This is a problem and you will need to consider upgrading your device to one that is supported.

If you need to ensure the privacy of your network usage then use a VPN to encrypt all your traffic. VPN is a protocol for encrypting all network traffic between two network points. The University has a VPN service that allows staff to connect to the internal University network from most places on the Internet. You will need to find a suitable VPN service for you.

The Bleeping Computer site is keeping an up to date list of patched devices at https://www.bleepingcomputer.com/news/security/list-of-firmware-and-driver-updates-for-krack-wpa2-vulnerability/

Summary

KRACK is an issue for all wireless networks. You should apply the security patches as soon as they become available.

Older devices may not receive security updates and are now at risk of becoming a gateway into your network and privacy. As such, sensible disposal is the preferred approach.

For devices where no patch is available you should assume that all traffic from that device can be spied on and potentially altered. Using a VPN to help mitigate this for you.

WPA2 “KRACK” – Technical notes

Tuesday, October 17th, 2017 | Jim Cheetham | Comments Off on WPA2 “KRACK” – Technical notes

KRACK (Key Reinstallation Attacks) is an effective attack on the WPA2 802.11i protocol used for protecting WiFi networks, published on October 16 2017 .

Because it is an attack on the protocol itself, every piece of equipment that can communicate over WiFi is affected. The attack must be carried out by a device that is in range of the network; i.e. this is a local attack, not a remote one.

TL;DR

Be WORRIED, but there is no need to PANIC. If there is a PATCH for your device, apply it as soon as possible. Otherwise, worry until there is.

KRACK tricks your wireless devices into resetting their encryption sessions to a known state, after which the attacker can read everything that they do, and can inject their own data into the network (i.e. a Man-in-the-Middle attack). This effectively turns your “private, secure” WPA2 network into a “public, insecure” one.

If you are safe operating your device on a public insecure network (e.g. airport or coffee-shop WiFi), then you will be equally safe operating it on a compromised WPA2 network.

KRACK does NOT steal your WiFi passwords or credentials.

The only effective fix for KRACK is on your client devices. PCs and laptops are likely to be patched quickly, mobile phones much more slowly if at all, and IoT devices are at serious risk.

KRACK References

  • KRACK website, https://www.krackattacks.com/
  • Key Reinstallation Attacks: Forcing Nonce Reuse in WPA2, https://papers.mathyvanhoef.com/ccs2017.pdf
  • CERT CVEs, http://www.kb.cert.org/vuls/id/228519
    • CVE-2017-13077: reinstallation of the pairwise key in the Four-way handshake
    • CVE-2017-13078: reinstallation of the group key in the Four-way handshake
    • CVE-2017-13079: reinstallation of the integrity group key in the Four-way handshake
    • CVE-2017-13080: reinstallation of the group key in the Group Key handshake
    • CVE-2017-13081: reinstallation of the integrity group key in the Group Key handshake
    • CVE-2017-13082: accepting a retransmitted Fast BSS Transition Reassociation Request and reinstalling the pairwise key while processing it
    • CVE-2017-13084: reinstallation of the STK key in the PeerKey handshake
    • CVE-2017-13086: reinstallation of the Tunneled Direct-Link Setup (TDLS) PeerKey (TPK) key in the TDLS handshake
    • CVE-2017-13087: reinstallation of the group key (GTK) when processing a Wireless Network Management (WNM) Sleep Mode Response frame
    • CVE-2017-13088: reinstallation of the integrity group key (IGTK) when processing a Wireless Network Management (WNM) Sleep Mode Response frame

Timeline

In early 2017 the researchers were finishing off another security publication when they realised that part of the OpenBSD network code for WiFi that they were discussing had a potential problem. By July 2017 a wide range of systems had been confirmed with this problem, and the CERT/CC co-ordinated a wider notification to OS and device vendors in late August. The public announcement was made on 16 October 2017.

Many vendors have made announcements and released patches already, more will be coming soon. OpenBSD patched early due to their relationship to the original discovery, some other vendors seem to have issued patches already but many important ones are yet to patch.

Patches

At the moment I’m getting my information from the CERT/CC and the Bleeping Computer website, but I’ll verify from original sources as soon as I can. https://www.bleepingcomputer.com/news/security/list-of-firmware-and-driver-updates-for-krack-wpa2-vulnerability/

No Patches

If you have a device using WiFi, and there are no patches for it, you should assume that all traffic from that device can be spied on and potentially altered. If you are encrypting your communications with TLS/SSL or something equivalent like OpenSSH, then all you are at risk from is a lack of privacy. However, you might need to consider implementing a VPN if you rely on plaintext or easily spoofed protocols.

Further Questions

If you have any further questions, please get in touch with the Information Security Office through the usual channels.