Detect Proc Memory in Microsoft Sentinel
Adversaries may inject malicious code into processes via the /proc filesystem in order to evade process-based defenses as well as possibly elevate privileges. Proc memory injection involves enumerating the memory of a process via the /proc filesystem (/proc/[pid]) then crafting a return-oriented programming (ROP) payload with available gadgets/instructions. Each running process has its own directory, which includes memory mappings. Proc memory injection is commonly performed by overwriting the target processes' stack using memory mappings provided by the /proc filesystem. This information can be used to enumerate offsets (including the stack) and gadgets otherwise hidden by ASLR. Once enumerated, the target processes' memory map within /proc/[pid]/maps can be overwritten using dd.
MITRE ATT&CK
- Technique
- T1055 Process Injection
- Sub-technique
- T1055.009 Proc Memory
- Canonical reference
- https://attack.mitre.org/techniques/T1055/009/
KQL Detection Query
// Detect /proc/[pid]/mem and /proc/[pid]/maps access for injection
Syslog
| where TimeGenerated > ago(24h)
| where SyslogMessage has_any ("/proc/") and SyslogMessage has_any ("mem", "maps", "syscall")
| where SyslogMessage !has "self" // exclude /proc/self/ access (legitimate)
| where SyslogMessage !has "gdb" and SyslogMessage !has "strace"
| extend ProcAccess = extract(@"/proc/(\d+)/(mem|maps|syscall)", 0, SyslogMessage)
| where isnotempty(ProcAccess)
| project TimeGenerated, Computer, SyslogMessage, ProcAccess, Facility, SeverityLevel
| sort by TimeGenerated descDetects access to /proc/[pid]/mem and /proc/[pid]/maps by monitoring Syslog and auditd for file access to these sensitive procfs paths. Excludes /proc/self/ access (which is legitimate self-inspection) and known debuggers. Direct access to another process's memory via /proc is a Linux injection technique that bypasses ptrace restrictions.
Data Sources
Required Tables
False Positives & Tuning
- System monitoring tools (top, htop, ps) reading /proc/[pid]/maps for memory statistics
- Container orchestration tools reading /proc filesystem for resource accounting
- Performance profiling tools (perf, valgrind) reading process memory maps
- Security scanning tools analyzing process memory layout for vulnerability assessment
Other platforms for T1055.009
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Read Target Process Memory Maps
Expected signal: auditd: open() syscall on /proc/<pid>/maps with the calling process (shell) details. The maps output shows memory regions including stack address needed for injection.
- Test 2DD-based /proc/pid/mem Write Simulation
Expected signal: auditd: open() on /proc/<pid>/maps. In a real injection: write() syscall to /proc/<pid>/mem would be logged. The dd command itself generates process creation events.
- Test 3Check /proc Hardening Configuration
Expected signal: No security telemetry — this is a configuration check. The output shows current hardening level.
References (5)
- https://attack.mitre.org/techniques/T1055/009/
- http://hick.org/code/skape/papers/needle.txt
- https://blog.gdssecurity.com/labs/2017/9/5/linux-based-inter-process-code-injection-without-ptrace2.html
- http://man7.org/linux/man-pages/man1/dd.1.html
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1055.009/T1055.009.md
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