Technical Written Scenario

Scenario 1: You receive an alert in your alert channel: "Allowed Activity - Severity 4/High IDS/IPS Alerts - From Internal--192.168.60.67--Win32/ZBot" Log sources available to you: Palo Alto NGFW WinEventLog:Security OSSEC HIDS Client email correspondence Shift logs and investigation notes Prior cases Internet With this information, please walk us through your investigation steps and how you might triage this alert. Scenario 2: While working on threat detection content development you observe some odd activity in the firewall logs. You notice a number of allowed HTTP connections outbound from a client's environment (Client IP - 192.168.10.15) towards a Russian IP address - 185.211.245.198. After further investigation you notice these HTTP connections seem to happen on a regular basis, even during off hours, in what looks to be a pattern. You know that this client's IP belongs to one of their user subnets and that this client has no business with or in Russia. We have no IDS or Anti-virus alerts for this device at this time. Please write up an escalation case communicating the observations, level of concern, and recommended actions to the client. Challenges Challenge 1 We've received an alert about a Brute Force attempt on this user. Based on the Windows Event Log below, please answer the following questions: 1. What is the account name associated with the login failures? 2. What system is this user attempting to authenticate from? 3. What domain controller are they attempting to authenticate to? 4. What does Logon Type 3 mean and what does that signify? 5. What type of authentication was used? 6. What's the other most common Windows logon authentication? 7. What do the Status and Sub Status codes mean and what does that tell us? 8. Can you conclude the investigation as a likely Brute Force event or a False Positive, and why or why not? 10/19/2020 01:03:38 PM LogName=Security SourceName=Microsoft Windows security auditing. EventCode=4625 EventType=0 Type=Information ComputerName=dendcprd02.client.com TaskCategory=Logon OpCode=Info RecordNumber=261208668 Keywords=Audit Failure Message=An account failed to log on. Subject: Security ID: NULL SID Account Name: - Account Domain: - Logon ID: 0x0 Logon Type: 3 Account For Which Logon Failed: Security ID: NULL SID Account Name: Sargento.Aquino Account Domain: ACME Failure Information: Failure Reason: The specified account's password has expired. Status: 0xC000006E Sub Status: 0xC0000071 Process Information: Caller Process ID: 0x0 Caller Process Name: - Network Information: Workstation Name: WS-RTJ88788FP Source Network Address: 10.14.9.47 Source Port: 52374 Detailed Authentication Information: Logon Process: NtLmSsp Authentication Package: NTLM Transited Services: - Package Name (NTLM only): - Key Length: 0 This event is generated when a logon request fails. It is generated on the computer where access was attempted. The Subject fields indicate the account on the local system which requested the logon. This is most commonly a service such as the Server service, or a local process such as Winlogon.exe or Services.exe. The Logon Type field indicates the kind of logon that was requested. The most common types are 2 (interactive) and 3 (network). The Process Information fields indicate which account and process on the system requested the logon. The Network Information fields indicate where a remote logon request originated. Workstation name is not always available and may be left blank in some cases. The authentication information fields provide detailed information about this specific logon request. - Transited services indicate which intermediate services have participated in this logon request. - Package name indicates which sub-protocol was used among the NTLM protocols. - Key length indicates the length of the generated session key. This will be 0 if no session key was requested.

Challenge 2 We've received an alert for a suspicious file on a host. Based on the provided event logs, please answer the following questions: 1. What's the name of the host where the file was found? 2. Who is the user associated with this event? 3. What's the name of the file? 4. How do you think the file got on the host to begin with? 5. Can you conclude the investigation as a True or a False Positive, and why or why not? Oct 1 18:47:09 10.100.45.105 timestamp=1601587024 date=2020-10-01 time=16:17:04 logver=2 id=96554 type="event" level="info" clientfeature="sandboxing" uid="B42E0D7515AF455D90FDB8A27C9863D4" devname="FortiClient-EMS" devid="FCT8004031349617" hostname="P7RSG887TPY" pcdomain="acme.local" deviceip=192.168.216.10 devicemac="00-09-0r-vv-89-02" vd="root" fctver="6.2.6.0951" fgtserial="N/A" emsserial="FCTEMS0000090672" usingpolicy="LT-CybereasonAV" os="Microsoft Windows 10 Enterprise Edition, 64-bit (build 18362)" user="ojulius@ACME" msg="file is submitted to Sandbox service" file="C:\\Users\\ojulius\\AppData\\Local\\Microsoft\\Windows\\INetCache\\Content.Outlook\\35UR1KUV\\report092520200944.pdf" checksum="76f671bc1e28cbdca269c0615ed4e9e398fdc7461de10ad1acdffd3ba1f79e62" ====== Oct 2 02:59:02 10.100.45.105 timestamp=1601625538 devhost="acm-denfsa01" devname="RefuseReceptacle" devid="FSA1KD3A15000102" logver=25 tzone=-18000 tz="CDT" date=2020-10-02 time=02:58:58 logid="0106000001" type="event" subtype="system" level="debug" user="system" ui="system" action="SNMP" status="success" reason="none" letype=2 msg="SNMP_v3 Trap: Risk Level:High Risk; Malware Name:N/A; File Name:report092520200944.pdf; SHA256:76f671bc1e28cbdca269c0615ed4e9e398fdc7461de10ad1acdffd3ba1f79e62; Time:1601625531; Victim IP:192.168.216.10; Rescan:0; Sender:N/A; Recipient:N/A;" Challenge 3 We've received an alert about suspicious activity from the firewall. Based on the provided logs below, please answer the follow questions: 1. What is the source of this activity? 2. What is the destination of the activity? 3. What part of the client's environment is this affecting? 4. What is the port being targeted by the attacker? 5. Is this something the client should be informed about? Why or why not? 6. What do you think is going on here? Oct 20 08:22:17 PA1.ACME.org 1,2020/10/20 08:22:16,013101004916,THREAT,vulnerability,2049,2020/10/20 08:22:16,192.241.217.192,88.66.59.62,192.241.217.192,10.6.200.239,owa.acme.org,,,web-browsing,vsys1,Untrust-L3,Trust-L3,ethernet1/11,ethernet1/9,Log Forwarding to ADCSyslog,2020/10/20 08:22:16,554581,1,38746,80,38746,80,0x412000,tcp,alert,"66.99.95.26/",ZGrab Application Layer Scanner Detection(57955),any,medium,client-to-server,6883821905258742491,0x2000000000000000,United States,United States,0,,0,,,1,,,,,,,,0,0,0,0,0,ADC-FW-A,PA1,,,,,0,,0,,N/A,info-leak,AppThreat-8332-6358,0x0,0,4294967295, ====== Oct 20 08:22:30 PA1.ACME.org 1,2020/10/20 08:22:30,013101004916,TRAFFIC,end,2049,2020/10/20 08:22:30,192.241.217.192,88.66.59.65,192.241.217.192,172.16.1.140,Direct Access - Inbound,,,web-browsing,vsys1,Untrust-L3,DMZ-L3,ethernet1/11,ethernet1/7,Log Forwarding to ADCSyslog,2020/10/20 08:22:30,389380,1,56902,80,56902,80,0x41001c,tcp,allow,1709,512,1197,10,2020/10/20 08:22:04,10,any,0,6883821905367363307,0x0,United States,United States,0,6,4,tcp-fin,0,0,0,0,ADC-FW-A,PA1,from-policy,,,0,,0,,N/A,0,0,0,0 ====== Oct 20 08:22:32 PA1.ACME.org 1,2020/10/20 08:22:31,013101004916,TRAFFIC,end,2049,2020/10/20 08:22:31,192.241.217.192,88.66.59.52,192.241.217.192,10.6.200.238,owa.acme.org,,,web-browsing,vsys1,Untrust-L3,Trust-L3,ethernet1/11,ethernet1/9,Log Forwarding to ADCSyslog,2020/10/20 08:22:31,404737,1,33274,80,33274,80,0x41001c,tcp,allow,1053,512,541,9,2020/10/20 08:22:05,10,any,0,6883821905367363898,0x0,United States,United States,0,6,3,tcp-fin,0,0,0,0,ADC-FW-A,PA1,from-policy,,,0,,0,,N/A,0,0,0,0

Solutions

Scenario 1

Allowed Activity - Severity 4/High IDS/IPS Alerts - From Internal--192.168.60.67--Win32/ZBot

Based on the scenario given, I can assume that there has been an intrusion and has already been infected on host system 192.168.60.67. Since the severity is high, we would contain the host system before any further damages occurs.

Using the Palo Alto New Generation Firewall we can see where and who the machine has interacted with. This NGFW now has becoming more and more advanced and it almost replaces a traditional SIEMs function. We can see where the regions are an if any sort of anomaly is on the network. From here we’re able to link and connect how the host is infected, and the number of times of events occurred from them. For instance, we would be able to see if 192.168.60.67 would be pinging out to a C2 server.

With WinLogEvent: Security, we would be able to see detailed information about what happened on the computer, suspicious Event 4720 user creation, and/or Event 4670 which changes a user’s permissions. We from here we would be able to determine the timeline of actions taken on this host computer.

Regarding OSSEC HIDS I would treat this as a SIEM solution. Of course, it isn’t a true SIEM, it does offer a wide variety of tools that would help understand the current situation. I would OSSEC + Kibana to triage the current standing of host 192.168.60.67. We can determine what websites host has visited, user inputs, src_ips and destinations.

We investigate further by digging up the history and email correspondents of the user. We would be able to any malicious emails, links, headers that the user might have clicked on. From there we could input suspicious IPS into our firewall to block them out from further interactions.

In addition, I would use Internet tools such as VirusTotal, CyberChef – to decode any encryptions, DNS Lookup, and Whoami to see where links would lead. Another great tool I would use would be Eric Zimmerman tools to help digest logs easier.

Regarding Prior cases, Shift logs, and investigation notes, I would search up the alert Win32/Zbot. Given the results, it seems to be an attack from a spam email, unsecure websites, or packaged with a trojan. From there I would see prior logs and determine if there was a suspicious escalation on the host computer. After determining if there is a runbook available.

Scenario 2

In this scenario, we are monitoring a Clients Firewall and environment. We observe one of the Clients IP addresses send packets outbound to a Russian Client IP. This is a regular occurrence. Clients IP is a legitimate subnet, but does no known business with Russia.

Case:

[1] Client has data packets sending out bound to Russia (185.211.245.198) [2] Regular occurrences of [1] happens even during off hours. [3] Client does not have any IDS or Anti-virus alerts installed on device. [4] Client only has outbound information, which means data could have been sent to a remote server.

The level of concern for this particular host is SEVERE. There is no installed IDS and Anti-Virus installed on this computer which basically means that this host is a free computer. Host can be used as a DDoS Botnet attack, information could have been breach, and privilege escalation has/had occurred and now is relaying packets back to C2 command server.

Recommendation:

· Contain Host Unit

· Investigate the infected units’ interaction with other hosts/company computers

· Inventory assets and information

· Recover undamaged host image file

· Reset host

· Install IDS / Anti-virus software

· Patch vulnerabilities

Challenge 1

1. Sargento.Aquino

2. ComputerName=dendcprd02.client.com

3. ACME

4. Network. Indicates where a remote logon request originated. Also shows if remote files or printers have been accessed

5. NtLmSsp

6. Registry, Service, Winlogon.exe

7. Status: 0xC000006E – User name and authentication information are valid, but account restriction has been prevented successfully Sub Status: 0xC0000071 – User logon with expired password

Status and sub status are codes of reason why a particular logon as either been failed or has been successful. These codes determine the category of the event, and the results proceeding. They are important indicators to tell investigators what is happening on the host computer at any given time.

8. Given the results I concluded that this event is a False Positive. This person could’ve forgotten; or used the current password which proved successful before, but it could have expired. Usually, brute force attempts are from remote services, however, seeing that the authentication information are valid that seems not to be the case.

Challenge 2

1. P7RSG887TPY

2. ojulius@ACME

3. report092520200944.pdf

4. This looks like a downloaded file that User Ojulius got from his email. He downloaded it into this pathway file="C:\\Users\\ojulius\\AppData\\Local\\Microsoft\\Windows\\INetCache\\Content.Outlook\\35UR1KUV\\report092520200944.pdf

We also can confirm this because of the action=”SNMP” which is the mail protocol.

5. This is a true positive because we can see that Ojulius downloaded a pdf file that proved to be malicious. If we search up the sha256 (76f671bc1e28cbdca269c0615ed4e9e398fdc7461de10ad1acdffd3ba1f79e62) on VirusTotal we are 24/60 rating as vendors flag this as malicious. We also see that this is not a report, but instead is a shipment_Mendez.pdf.

Challenge 3

To be completely honest, firewall log activity is one where I haven’t had much training on. So here is my attempt to assess, parse, and understand it. I understand this is one of my weak points, and I am willing to learn how to digest and deploy firewalls.

1. 6.6.99.95

2. Owa.acme.org

3. ADCSyslog

4. Port 512

5. Yes because of the noted Threat Vulnerability 2049 in 2020. CVE-2020-2049 Cortex XDR is an improper control of loaded DLL which leads to a local privilege escalation.

6. What I think is going on is an attempt of lateral privilege escalation on the network. The attacker would be able to create files in a Windows environment root directory.