Suspicious Electron Application Child Processes

Detects suspicious child processes of electron apps (teams, discord, slack, etc.). This could be a potential sign of ".asar" file tampering (See reference section for more information) or binary execution proxy through specific CLI arguments (see related rule)

Sigma rule (View on GitHub)

 1title: Suspicious Electron Application Child Processes
 2id: f26eb764-fd89-464b-85e2-dc4a8e6e77b8
 3related:
 4    - id: 378a05d8-963c-46c9-bcce-13c7657eac99
 5      type: similar
 6status: test
 7description: |
 8        Detects suspicious child processes of electron apps (teams, discord, slack, etc.). This could be a potential sign of ".asar" file tampering (See reference section for more information) or binary execution proxy through specific CLI arguments (see related rule)
 9references:
10    - https://taggart-tech.com/quasar-electron/
11    - https://github.com/mttaggart/quasar
12    - https://positive.security/blog/ms-officecmd-rce
13    - https://lolbas-project.github.io/lolbas/Binaries/Msedge/
14    - https://lolbas-project.github.io/lolbas/Binaries/Teams/
15    - https://lolbas-project.github.io/lolbas/Binaries/msedgewebview2/
16    - https://medium.com/@MalFuzzer/one-electron-to-rule-them-all-dc2e9b263daf
17author: Nasreddine Bencherchali (Nextron Systems)
18date: 2022/10/21
19modified: 2024/07/12
20tags:
21    - attack.execution
22logsource:
23    category: process_creation
24    product: windows
25detection:
26    selection_parent:
27        ParentImage|endswith:
28            # Add more electron based app to the list
29            - '\chrome.exe' # Might require additional tuning
30            - '\discord.exe'
31            - '\GitHubDesktop.exe'
32            - '\keybase.exe'
33            - '\msedge.exe'
34            - '\msedgewebview2.exe'
35            - '\msteams.exe'
36            - '\slack.exe'
37            - '\teams.exe'
38            # - '\code.exe' # Prone to a lot of FPs. Requires an additional baseline
39    selection_child_image:
40        Image|endswith:
41            # Add more suspicious/unexpected paths
42            - '\cmd.exe'
43            - '\cscript.exe'
44            - '\mshta.exe'
45            - '\powershell.exe'
46            - '\pwsh.exe'
47            - '\regsvr32.exe'
48            - '\whoami.exe'
49            - '\wscript.exe'
50    selection_child_paths:
51        Image|contains:
52            # Add more suspicious/unexpected paths
53            - ':\ProgramData\'
54            - ':\Temp\'
55            - '\AppData\Local\Temp\'
56            - '\Users\Public\'
57            - '\Windows\Temp\'
58    filter_optional_discord:
59        ParentImage|endswith: '\Discord.exe'
60        Image|endswith: '\cmd.exe'
61        CommandLine|contains: '\NVSMI\nvidia-smi.exe'
62    condition: selection_parent and 1 of selection_child_* and not 1 of filter_optional_*
63falsepositives:
64    - Unknown
65# Increase the level once FP rate is reduced (see status)
66level: medium

References

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