Query: write Sigma for Detects the creation of files with suspicious file extensions in the temporary directory that Outlook uses when opening
Matching passage: Sigma rule: Detects the creation of files with suspicious file extensions in the temporary directory that Outlook uses when opening. Logsource: windows / file_event. Rule: title: Suspicious File Created in Outlook Temporary Directory id: fabb0e80-030c-4e3e-a104-d09676991ac3 related: - id: f748c45a-f8d3-4e6f-b617-fe176f695b8f type: obsolete status: experimental description: 'Detects the creation of files with suspicious file extensions in the temporary directory that Outlook uses when opening attachments. This can be used to detect spear-phishing campaigns that use suspicious files as attachments, which may contain malicious code. ' references: - https://vipre.com/blog/svg-phishing-attacks-the-new-trick-in-the-cybercriminals-playbook/ - https://thecyberexpress.com/rogue-rdp-files-used-in-ukraine-cyberattacks/ - https://www.microsoft.com/en-us/security/blog/2024/10/29/midnight-blizzard-conducts-large-scale-spear-phishing-campaign-using-rdp-files/ author: Florian Roth (Nextron Systems), Swachchhanda Shrawan Poudel (Nextron Systems) date: 2025-07-22 tags: - attack.initial-access - attack.t1566.001 logsource: product: windows category: file_event detection: selection_extension: TargetFilename|endswith: - .cpl - .hta - .iso - .rdp - .svg - .vba - .vbe - .vbs selection_location: - TargetFilename|contains: - \AppData\Local\Packages\Microsoft.Outlook_ - \AppData\Local\Microsoft\Olk\Attachments\ - TargetFilename|contains|all: - \AppData\Local\Microsoft\Windows\ - \Content.Outlook\ condition: all of selection_* falsepositives: - Opening of headers or footers in email signatures that include SVG images or legitimate SVG attachments level: high
Near-miss passage: Sigma rule: Detects abusing Azure Browser SSO by requesting OAuth 2.0 refresh tokens for an Azure-AD-authenticated Windows user (i.e. Logsource: windows / image_load. Rule: title: Potential Azure Browser SSO Abuse id: 50f852e6-af22-4c78-9ede-42ef36aa3453 status: test description: 'Detects abusing Azure Browser SSO by requesting OAuth 2.0 refresh tokens for an Azure-AD-authenticated Windows user (i.e. the machine is joined to Azure AD and a user logs in with their Azure AD account) wanting to perform SSO authentication in the browser. An attacker can use this to authenticate to Azure AD in a browser as that user. ' references: - https://posts.specterops.io/requesting-azure-ad-request-tokens-on-azure-ad-joined-machines-for-browser-sso-2b0409caad30 author: Den Iuzvyk date: 2020-07-15 modified: 2023-04-18 tags: - attack.persistence - attack.privilege-escalation - attack.execution - attack.stealth - attack.t1574.001 logsource: category: image_load product: windows detection: selection: ImageLoaded: C:\Windows\System32\MicrosoftAccountTokenProvider.dll filter_main_bgtaskhost: Image|startswith: - C:\Windows\System32\ - C:\Windows\SysWOW64\ Image|endswith: \BackgroundTaskHost.exe filter_optional_devenv: Image|startswith: - C:\Program Files\Microsoft Visual Studio\ - C:\Program Files (x86)\Microsoft Visual Studio\ Image|endswith: \IDE\devenv.exe filter_optional_ie: Image: - C:\Program Files (x86)\Internet Explorer\iexplore.exe - C:\Program Files\Internet Explorer\iexplore.exe filter_optional_edge_1: - Image|startswith: C:\Program Files (x86)\Microsoft\EdgeWebView\Application\ - Image|endswith: \WindowsApps\MicrosoftEdge.exe - Image: - C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe - C:\Program Files\Microsoft\Edge\Application\msedge.exe filter_optional_edge_2: Image|startswith: - C:\Program Files (x86)\Microsoft\EdgeCore\ - C:\Program Files\Microsoft\EdgeCore\ Image|endswith: - \msedge.exe - \msedgewebview2.exe filter_optional_onedrive: Image|endswith: \AppData\Local\Microsoft\OneDrive\OneDrive.exe filter_optional_null: Image: null condition: selection and not 1 of filter_main_* and not 1 of filter_optional_* falsepositives: - False positives are expected since this rules is only looking for the DLL load event. This rule is better used in correlation with related activity level: low