Adversaries may inject malicious code into processes via thread local storage (TLS) callbacks in order to evade process-based defenses as well as possibly elevate privileges. TLS callback injection is a method of executing arbitrary code in the address space of a separate live process.
TLS callback injection involves manipulating pointers inside a portable executable (PE) to redirect a process to malicious code before reaching the code's legitimate entry point. TLS callbacks are normally used by the OS to setup and/or cleanup data used by threads. Manipulating TLS callbacks may be performed by allocating and writing to specific offsets within a process’ memory space using other Process Injection techniques such as Process Hollowing.(Citation: FireEye TLS Nov 2017)
Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via TLS callback injection may also evade detection from security products since the execution is masked under a legitimate process.
View in MITRE ATT&CK®| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| AC-6 | Least Privilege | Protects | T1055.005 | Thread Local Storage | |
| SC-18 | Mobile Code | Protects | T1055.005 | Thread Local Storage | |
| SC-7 | Boundary Protection | Protects | T1055.005 | Thread Local Storage | |
| SI-2 | Flaw Remediation | Protects | T1055.005 | Thread Local Storage | |
| SI-3 | Malicious Code Protection | Protects | T1055.005 | Thread Local Storage | |
| SI-4 | System Monitoring | Protects | T1055.005 | Thread Local Storage |
| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| alerts_for_windows_machines | Alerts for Windows Machines | technique_scores | T1055.005 | Thread Local Storage |
Comments
Injection attacks are specifically cited as a detection focus for Fileless Attack Detection, which is part of this control, with even more specific references to Process Hollowing, executable image injection, and threads started in a dynamically allocated code segment. Detection is periodic at an unknown rate. The following alerts may be generated: "Fileless attack technique detected", "Fileless attack behavior detected", "Fileless attack toolkit detected", "Suspicious SVCHOST process executed".
References
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| azure_defender_for_app_service | Azure Defender for App Service | technique_scores | T1055.005 | Thread Local Storage |
Comments
Injection attacks are specifically cited as a detection focus for Fileless Attack Detection, which is part of this control, with even more specific references to Process Hollowing, executable image injection, and threads started in a dynamically allocated code segment. Detection is periodic at an unknown rate.
References
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