Adversaries may transfer tools or other files from an external system into a compromised environment. Tools or files may be copied from an external adversary-controlled system to the victim network through the command and control channel or through alternate protocols such as [ftp](https://attack.mitre.org/software/S0095). Once present, adversaries may also transfer/spread tools between victim devices within a compromised environment (i.e. [Lateral Tool Transfer](https://attack.mitre.org/techniques/T1570)).
On Windows, adversaries may use various utilities to download tools, such as `copy`, `finger`, [certutil](https://attack.mitre.org/software/S0160), and [PowerShell](https://attack.mitre.org/techniques/T1059/001) commands such as <code>IEX(New-Object Net.WebClient).downloadString()</code> and <code>Invoke-WebRequest</code>. On Linux and macOS systems, a variety of utilities also exist, such as `curl`, `scp`, `sftp`, `tftp`, `rsync`, `finger`, and `wget`.(Citation: t1105_lolbas) A number of these tools, such as `wget`, `curl`, and `scp`, also exist on ESXi. After downloading a file, a threat actor may attempt to verify its integrity by checking its hash value (e.g., via `certutil -hashfile`).(Citation: Google Cloud Threat Intelligence COSCMICENERGY 2023)
Adversaries may also abuse installers and package managers, such as `yum` or `winget`, to download tools to victim hosts. Adversaries have also abused file application features, such as the Windows `search-ms` protocol handler, to deliver malicious files to victims through remote file searches invoked by [User Execution](https://attack.mitre.org/techniques/T1204) (typically after interacting with [Phishing](https://attack.mitre.org/techniques/T1566) lures).(Citation: T1105: Trellix_search-ms)
Files can also be transferred using various [Web Service](https://attack.mitre.org/techniques/T1102)s as well as native or otherwise present tools on the victim system.(Citation: PTSecurity Cobalt Dec 2016) In some cases, adversaries may be able to leverage services that sync between a web-based and an on-premises client, such as Dropbox or OneDrive, to transfer files onto victim systems. For example, by compromising a cloud account and logging into the service's web portal, an adversary may be able to trigger an automatic syncing process that transfers the file onto the victim's machine.(Citation: Dropbox Malware Sync)
A vulnerability in the web-based management interface of Cisco Data Center Network Manager (DCNM) could allow an unauthenticated, remote attacker to upload arbitrary files on an affected device. The vulnerability is due to incorrect permission settings in affected DCNM software. An attacker could exploit this vulnerability by uploading specially crafted data to the affected device. A successful exploit could allow the attacker to write arbitrary files on the filesystem and execute code with root privileges on the affected device.
A vulnerability in the client application for iOS of Cisco Webex Teams could allow an authenticated, remote attacker to upload arbitrary files within the scope of the iOS application. The vulnerability is due to improper input validation in the client application. An attacker could exploit this vulnerability by sending a malicious file to a targeted user and persuading the user to manually open it. An exploit could allow the attacker to overwrite sensitive application files and eventually cause a denial of service (DoS) condition by foreclosing future access to the system to the targeted user. This vulnerability is fixed in version 3.13.26920.