Передача управляющих сигналов в трафике
Sub-techniques (2)
| ID | Name |
|---|---|
| .001 | Простукивание портов |
| .002 | Фильтры сокета |
Adversaries may use traffic signaling to hide open ports or other malicious functionality used for persistence or command and control. Traffic signaling involves the use of a magic value or sequence that must be sent to a system to trigger a special response, such as opening a closed port or executing a malicious task. This may take the form of sending a series of packets with certain characteristics before a port will be opened that the adversary can use for command and control. Usually this series of packets consists of attempted connections to a predefined sequence of closed ports (i.e. Port Knocking), but can involve unusual flags, specific strings, or other unique characteristics. After the sequence is completed, opening a port may be accomplished by the host-based firewall, but could also be implemented by custom software. Adversaries may also communicate with an already open port, but the service listening on that port will only respond to commands or trigger other malicious functionality if passed the appropriate magic value(s). The observation of the signal packets to trigger the communication can be conducted through different methods. One means, originally implemented by Cd00r (Citation: Hartrell cd00r 2002), is to use the libpcap libraries to sniff for the packets in question. Another method leverages raw sockets, which enables the malware to use ports that are already open for use by other programs. On network devices, adversaries may use crafted packets to enable Network Device Authentication for standard services offered by the device such as telnet. Such signaling may also be used to open a closed service port such as telnet, or to trigger module modification of malware implants on the device, adding, removing, or changing malicious capabilities. Adversaries may use crafted packets to attempt to connect to one or more (open or closed) ports, but may also attempt to connect to a router interface, broadcast, and network address IP on the same port in order to achieve their goals and objectives.(Citation: Cisco Synful Knock Evolution)(Citation: Mandiant - Synful Knock)(Citation: Cisco Blog Legacy Device Attacks) To enable this traffic signaling on embedded devices, adversaries must first achieve and leverage Patch System Image due to the monolithic nature of the architecture. Adversaries may also use the Wake-on-LAN feature to turn on powered off systems. Wake-on-LAN is a hardware feature that allows a powered down system to be powered on, or woken up, by sending a magic packet to it. Once the system is powered on, it may become a target for lateral movement.(Citation: Bleeping Computer - Ryuk WoL)(Citation: AMD Magic Packet)
Примеры процедур |
|
| Название | Описание |
|---|---|
|
During Cutting Edge, threat actors sent a magic 48-byte sequence to enable the PITSOCK backdoor to communicate via the `/tmp/clientsDownload.sock` socket.(Citation: Mandiant Cutting Edge Part 3 February 2024) |
|
| ZIPLINE |
ZIPLINE can identify a specific string in intercepted network traffic, `SSH-2.0-OpenSSH_0.3xx.`, to trigger its command functionality.(Citation: Mandiant Cutting Edge January 2024) |
| BUSHWALK |
BUSHWALK can modify the `DSUserAgentCap.pm` Perl module on Ivanti Connect Secure VPNs and either activate or deactivate depending on the value of the user agent in incoming HTTP requests.(Citation: Mandiant Cutting Edge Part 3 February 2024) |
| Penquin |
Penquin will connect to C2 only after sniffing a "magic packet" value in TCP or UDP packets matching specific conditions.(Citation: Leonardo Turla Penquin May 2020)(Citation: Kaspersky Turla Penquin December 2014) |
| SYNful Knock |
SYNful Knock can be sent instructions via special packets to change its functionality. Code for new functionality can be included in these messages.(Citation: Mandiant - Synful Knock) |
| Winnti for Linux |
Winnti for Linux has used a passive listener, capable of identifying a specific magic value before executing tasking, as a secondary command and control (C2) mechanism.(Citation: Chronicle Winnti for Linux May 2019) |
| Chaos |
Chaos provides a reverse shell is triggered upon receipt of a packet with a special string, sent to any port.(Citation: Chaos Stolen Backdoor) |
| Umbreon |
Umbreon provides additional access using its backdoor Espeon, providing a reverse shell upon receipt of a special packet.(Citation: Umbreon Trend Micro) |
| Kobalos |
Kobalos is triggered by an incoming TCP connection to a legitimate service from a specific source port.(Citation: ESET Kobalos Feb 2021)(Citation: ESET Kobalos Jan 2021) |
| Pandora |
Pandora can identify if incoming HTTP traffic contains a token and if so it will intercept the traffic and process the received command.(Citation: Trend Micro Iron Tiger April 2021) |
| Ryuk |
Ryuk has used Wake-on-Lan to power on turned off systems for lateral movement.(Citation: Bleeping Computer - Ryuk WoL) |
| Uroburos |
Uroburos can intercept the first client to server packet in the 3-way TCP handshake to determine if the packet contains the correct unique value for a specific Uroburos implant. If the value does not match, the packet and the rest of the TCP session are passed to the legitimate listening application.(Citation: Joint Cybersecurity Advisory AA23-129A Snake Malware May 2023) |
Контрмеры |
|
| Контрмера | Описание |
|---|---|
| Port Knocking Mitigation |
Mitigation of some variants of this technique could be achieved through the use of stateful firewalls, depending upon how it is implemented. |
| Filter Network Traffic |
Use network appliances to filter ingress or egress traffic and perform protocol-based filtering. Configure software on endpoints to filter network traffic. |
| Disable or Remove Feature or Program |
Remove or deny access to unnecessary and potentially vulnerable software to prevent abuse by adversaries. |
Обнаружение
Record network packets sent to and from the system, looking for extraneous packets that do not belong to established flows.
The Wake-on-LAN magic packet consists of 6 bytes of FF followed by sixteen repetitions of the target system's IEEE address. Seeing this string anywhere in a packet's payload may be indicative of a Wake-on-LAN attempt.(Citation: GitLab WakeOnLAN)
Ссылки
- Perry, David. (2020, August 11). WakeOnLAN (WOL). Retrieved February 17, 2021.
- Omar Santos. (2020, October 19). Attackers Continue to Target Legacy Devices. Retrieved October 20, 2020.
- Hartrell, Greg. (2002, August). Get a handle on cd00r: The invisible backdoor. Retrieved October 13, 2018.
- Graham Holmes. (2015, October 8). Evolution of attacks on Cisco IOS devices. Retrieved October 19, 2020.
- Bill Hau, Tony Lee, Josh Homan. (2015, September 15). SYNful Knock - A Cisco router implant - Part I. Retrieved October 19, 2020.
- AMD. (1995, November 1). Magic Packet Technical White Paper. Retrieved February 17, 2021.
- Abrams, L. (2021, January 14). Ryuk Ransomware Uses Wake-on-Lan To Encrypt Offline Devices. Retrieved February 11, 2021.
- Lin, M. et al. (2024, February 27). Cutting Edge, Part 3: Investigating Ivanti Connect Secure VPN Exploitation and Persistence Attempts. Retrieved March 1, 2024.
- McLellan, T. et al. (2024, January 12). Cutting Edge: Suspected APT Targets Ivanti Connect Secure VPN in New Zero-Day Exploitation. Retrieved February 27, 2024.
- Leonardo. (2020, May 29). MALWARE TECHNICAL INSIGHT TURLA “Penquin_x64”. Retrieved March 11, 2021.
- Baumgartner, K. and Raiu, C. (2014, December 8). The ‘Penquin’ Turla. Retrieved March 11, 2021.
- Chronicle Blog. (2019, May 15). Winnti: More than just Windows and Gates. Retrieved April 29, 2020.
- Sebastian Feldmann. (2018, February 14). Chaos: a Stolen Backdoor Rising Again. Retrieved March 5, 2018.
- Fernando Mercês. (2016, September 5). Pokémon-themed Umbreon Linux Rootkit Hits x86, ARM Systems. Retrieved March 5, 2018.
- M.Leveille, M., Sanmillan, I. (2021, January). A WILD KOBALOS APPEARS Tricksy Linux malware goes after HPCs. Retrieved August 24, 2021.
- M.Leveille, M., Sanmillan, I. (2021, February 2). Kobalos – A complex Linux threat to high performance computing infrastructure. Retrieved August 24, 2021.
- Lunghi, D. and Lu, K. (2021, April 9). Iron Tiger APT Updates Toolkit With Evolved SysUpdate Malware. Retrieved November 12, 2021.
- Jamie Harries. (2022, May 25). Hunting a Global Telecommunications Threat: DecisiveArchitect and Its Custom Implant JustForFun. Retrieved October 18, 2022.
- FBI et al. (2023, May 9). Hunting Russian Intelligence “Snake” Malware. Retrieved June 8, 2023.
Связанные риски
Каталоги
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