Query: stealth using BITS Jobs
Matching passage: T1197 BITS Jobs. Tactics: stealth, persistence, execution. Description: Adversaries may abuse BITS jobs to persistently execute code and perform various background tasks. Windows Background Intelligent Transfer Service (BITS) is a low-bandwidth, asynchronous file transfer mechanism exposed through [Component Object Model](https://attack.mitre.org/techniques/T1559/001) (COM).(Citation: Microsoft COM)(Citation: Microsoft BITS) BITS is commonly used by updaters, messengers, and other applications preferred to operate in the background (using available idle bandwidth) without interrupting other networked applications. File transfer tasks are implemented as BITS jobs, which contain a queue of one or more file operations. The interface to create and manage BITS jobs is accessible through [PowerShell](https://attack.mitre.org/techniques/T1059/001) and the [BITSAdmin](https://attack.mitre.org/software/S0190) tool.(Citation: Microsoft BITS)(Citation: Microsoft BITSAdmin) Adversaries may abuse BITS to download (e.g. [Ingress Tool Transfer](https://attack.mitre.org/techniques/T1105)), execute, and even clean up after running malicious code (e.g. [Indicator Removal](https://attack.mitre.org/techniques/T1070)). BITS tasks are self-contained in the BITS job database, without new files or registry modifications, and often permitted by host firewalls.(Citation: CTU BITS Malware June 2016)(Citation: Mondok Windows PiggyBack BITS May 2007)(Citation: Symantec BITS May 2007) BITS enabled execution may also enable persistence by creating long-standing jobs (the default maximum lifetime is 90 days and extendable) or invoking an arbitrary program when a job completes or errors (including after system reboots).(Citation: PaloAlto UBoatRAT Nov 2017)(Citation: CTU BITS Malware June 2016) BITS upload functionalities can also be used to perform [Exfiltration Over Alternative Protocol](https://attack.mitre.org/techniques/T1048).(Citation: CTU BITS Malware June 2016)
Near-miss passage: T1027.006 HTML Smuggling. Tactics: stealth. Description: Adversaries may smuggle data and files past content filters by hiding malicious payloads inside of seemingly benign HTML files. HTML documents can store large binary objects known as JavaScript Blobs (immutable data that represents raw bytes) that can later be constructed into file-like objects. Data may also be stored in Data URLs, which enable embedding media type or MIME files inline of HTML documents. HTML5 also introduced a download attribute that may be used to initiate file downloads.(Citation: HTML Smuggling Menlo Security 2020)(Citation: Outlflank HTML Smuggling 2018) Adversaries may deliver payloads to victims that bypass security controls through HTML Smuggling by abusing JavaScript Blobs and/or HTML5 download attributes. Security controls such as web content filters may not identify smuggled malicious files inside of HTML/JS files, as the content may be based on typically benign MIME types such as <code>text/plain</code> and/or <code>text/html</code>. Malicious files or data can be obfuscated and hidden inside of HTML files through Data URLs and/or JavaScript Blobs and can be deobfuscated when they reach the victim (i.e. [Deobfuscate/Decode Files or Information](https://attack.mitre.org/techniques/T1140)), potentially bypassing content filters. For example, JavaScript Blobs can be abused to dynamically generate malicious files in the victim machine and may be dropped to disk by abusing JavaScript functions such as <code>msSaveBlob</code>.(Citation: HTML Smuggling Menlo Security 2020)(Citation: MSTIC NOBELIUM May 2021)(Citation: Outlflank HTML Smuggling 2018)(Citation: nccgroup Smuggling HTA 2017)