Куда я попал?
SECURITM это SGRC система, ? автоматизирующая процессы в службах информационной безопасности. SECURITM помогает построить и управлять ИСПДн, КИИ, ГИС, СМИБ/СУИБ, банковскими системами защиты.
А еще SECURITM это место для обмена опытом и наработками для служб безопасности.

Modify System Image:  Внесение исправлений в образ ОС

Adversaries may modify the operating system of a network device to introduce new capabilities or weaken existing defenses.(Citation: Killing the myth of Cisco IOS rootkits) (Citation: Killing IOS diversity myth) (Citation: Cisco IOS Shellcode) (Citation: Cisco IOS Forensics Developments) (Citation: Juniper Netscreen of the Dead) Some network devices are built with a monolithic architecture, where the entire operating system and most of the functionality of the device is contained within a single file. Adversaries may change this file in storage, to be loaded in a future boot, or in memory during runtime. To change the operating system in storage, the adversary will typically use the standard procedures available to device operators. This may involve downloading a new file via typical protocols used on network devices, such as TFTP, FTP, SCP, or a console connection. The original file may be overwritten, or a new file may be written alongside of it and the device reconfigured to boot to the compromised image. To change the operating system in memory, the adversary typically can use one of two methods. In the first, the adversary would make use of native debug commands in the original, unaltered running operating system that allow them to directly modify the relevant memory addresses containing the running operating system. This method typically requires administrative level access to the device. In the second method for changing the operating system in memory, the adversary would make use of the boot loader. The boot loader is the first piece of software that loads when the device starts that, in turn, will launch the operating system. Adversaries may use malicious code previously implanted in the boot loader, such as through the ROMMONkit method, to directly manipulate running operating system code in memory. This malicious code in the bootloader provides the capability of direct memory manipulation to the adversary, allowing them to patch the live operating system during runtime. By modifying the instructions stored in the system image file, adversaries may either weaken existing defenses or provision new capabilities that the device did not have before. Examples of existing defenses that can be impeded include encryption, via Weaken Encryption, authentication, via Network Device Authentication, and perimeter defenses, via Network Boundary Bridging. Adding new capabilities for the adversary’s purpose include Keylogging, Multi-hop Proxy, and Port Knocking. Adversaries may also compromise existing commands in the operating system to produce false output to mislead defenders. When this method is used in conjunction with Downgrade System Image, one example of a compromised system command may include changing the output of the command that shows the version of the currently running operating system. By patching the operating system, the adversary can change this command to instead display the original, higher revision number that they replaced through the system downgrade. When the operating system is patched in storage, this can be achieved in either the resident storage (typically a form of flash memory, which is non-volatile) or via TFTP Boot. When the technique is performed on the running operating system in memory and not on the stored copy, this technique will not survive across reboots. However, live memory modification of the operating system can be combined with ROMMONkit to achieve persistence.

ID: T1601.001
Относится к технике:  T1601
Тактика(-и): Defense Evasion
Платформы: Network
Требуемые разрешения: Administrator
Источники данных: File: File Modification
Версия: 1.0
Дата создания: 19 Oct 2020
Последнее изменение: 22 Oct 2020

Примеры процедур

Название Описание
SYNful Knock

SYNful Knock is malware that is inserted into a network device by patching the operating system image.(Citation: Mandiant - Synful Knock)(Citation: Cisco Synful Knock Evolution)

Контрмеры

Контрмера Описание
Boot Integrity

Use secure methods to boot a system and verify the integrity of the operating system and loading mechanisms.

Code Signing

Enforce binary and application integrity with digital signature verification to prevent untrusted code from executing.

Credential Access Protection

Use capabilities to prevent successful credential access by adversaries; including blocking forms of credential dumping.

Privileged Account Management

Manage the creation, modification, use, and permissions associated to privileged accounts, including SYSTEM and root.

Multi-factor Authentication

Use two or more pieces of evidence to authenticate to a system; such as username and password in addition to a token from a physical smart card or token generator.

Password Policies

Set and enforce secure password policies for accounts.

Обнаружение

Compare the checksum of the operating system file with the checksum of a known good copy from a trusted source. Some embedded network device platforms may have the capability to calculate the checksum of the file, while others may not. Even for those platforms that have the capability, it is recommended to download a copy of the file to a trusted computer to calculate the checksum with software that is not compromised.(Citation: Cisco IOS Software Integrity Assurance - Image File Verification) Many vendors of embedded network devices can provide advanced debugging support that will allow them to work with device owners to validate the integrity of the operating system running in memory. If a compromise of the operating system is suspected, contact the vendor technical support and seek such services for a more thorough inspection of the current running system. (Citation: Cisco IOS Software Integrity Assurance - Run-Time Memory Verification)

Ссылки

  1. Cisco. (n.d.). Cisco IOS Software Integrity Assurance - Cisco IOS Run-Time Memory Integrity Verification. Retrieved October 19, 2020.
  2. Cisco. (n.d.). Cisco IOS Software Integrity Assurance - Cisco IOS Image File Verification. Retrieved October 19, 2020.
  3. Graeme Neilson . (2009, August). Juniper Netscreen of the Dead. Retrieved October 20, 2020.
  4. Felix 'FX' Lindner. (2008, February). Developments in Cisco IOS Forensics. Retrieved October 21, 2020.
  5. George Nosenko. (2015). CISCO IOS SHELLCODE: ALL-IN-ONE. Retrieved October 21, 2020.
  6. Ang Cui, Jatin Kataria, Salvatore J. Stolfo. (2011, August). Killing the myth of Cisco IOS diversity: recent advances in reliable shellcode design. Retrieved October 20, 2020.
  7. Sebastian 'topo' Muñiz. (2008, May). Killing the myth of Cisco IOS rootkits. Retrieved October 20, 2020.
  8. Cisco. (n.d.). Cisco IOS Software Integrity Assurance - Deploy Signed IOS. Retrieved October 21, 2020.
  9. Graham Holmes. (2015, October 8). Evolution of attacks on Cisco IOS devices. Retrieved October 19, 2020.
  10. Bill Hau, Tony Lee, Josh Homan. (2015, September 15). SYNful Knock - A Cisco router implant - Part I. Retrieved October 19, 2020.
  11. Cisco. (n.d.). Cisco IOS Software Integrity Assurance - Secure Boot. Retrieved October 19, 2020.
  12. Cisco. (n.d.). Cisco IOS Software Integrity Assurance - TACACS. Retrieved October 19, 2020.
  13. Cisco. (n.d.). Cisco IOS Software Integrity Assurance - Credentials Management. Retrieved October 19, 2020.
  14. Grassi, P., et al. (2017, December 1). SP 800-63-3, Digital Identity Guidelines. Retrieved January 16, 2019.

Связанные риски

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