Detect SVG Smuggling in Sumo Logic CSE
Adversaries may smuggle data and files past content filters by hiding malicious payloads inside of seemingly benign SVG files. SVGs are vector-based image files constructed using XML and can legitimately include <script> tags, enabling adversaries to embed malicious JavaScript payloads. SVGs may appear less suspicious to users than other executable file types since they are often treated as image files. SVG smuggling can assemble or download malicious payloads, redirect users to malicious websites, or display interactive content such as fake login forms. SVG Smuggling may be used in conjunction with HTML Smuggling where an SVG with a malicious payload is included inside an HTML file.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1027 Obfuscated Files or Information
- Sub-technique
- T1027.017 SVG Smuggling
- Canonical reference
- https://attack.mitre.org/techniques/T1027/017/
Sumo Detection Query
_sourceCategory=*windows* (EventID=1 OR EventID=11)
| parse regex "<EventID.*?>(?P<EventID>\d+)</EventID>" nodrop
| parse regex "<Image.*?>(?P<Image>[^<]+)</Image>" nodrop
| parse regex "<CommandLine.*?>(?P<CommandLine>[^<]+)</CommandLine>" nodrop
| parse regex "<ParentImage.*?>(?P<ParentImage>[^<]+)</ParentImage>" nodrop
| parse regex "<ParentCommandLine.*?>(?P<ParentCommandLine>[^<]+)</ParentCommandLine>" nodrop
| parse regex "<TargetFilename.*?>(?P<TargetFilename>[^<]+)</TargetFilename>" nodrop
| parse regex "<User.*?>(?P<User>[^<]+)</User>" nodrop
| parse regex "<Computer>(?P<Computer>[^<]+)</Computer>" nodrop
| where EventID in ("1", "11")
| where ParentImage matches /(?i)(chrome|msedge|firefox|iexplore|opera|brave|outlook|thunderbird|winmail)\.exe/
| where (EventID == "1" AND Image matches /(?i)(cmd|powershell|pwsh|wscript|cscript|mshta|rundll32|regsvr32|certutil|msiexec|bitsadmin|curl|wget)\.exe/)
OR (EventID == "11" AND TargetFilename matches /(?i)\.svg$/)
| if (EventID == "11", "SVG_File_Written",
if (CommandLine matches /(?i)\.svg/ OR ParentCommandLine matches /(?i)\.svg/,
"SVG_Context_Process_Spawn", "Browser_Mail_Suspicious_Child_Process")) as DetectionType
| if (CommandLine matches /(?i)(downloads|temp|appdata)/, 1, 0) as DropPathBonus
| if (CommandLine matches /(?i)\.svg/ OR ParentCommandLine matches /(?i)\.svg/, 1, 0) as SvgContextBonus
| (1 + DropPathBonus + SvgContextBonus) as RiskScore
| fields _messageTime, Computer, User, Image, CommandLine, ParentImage, ParentCommandLine, TargetFilename, DetectionType, RiskScore
| sort by _messageTime descDetects SVG Smuggling (T1027.017) in Sumo Logic by parsing raw Sysmon XML event data inline. Extracts process and file event fields from EventID 1 (Process Create) and EventID 11 (File Create) records, then applies regex filters to identify browser or mail client parent processes spawning suspicious LOLBins or writing SVG files. Classifies each match into one of three DetectionType categories and computes a RiskScore based on SVG command-line context and drop-path indicators. Assumes Sysmon events are forwarded to Sumo Logic in raw XML format under a _sourceCategory containing 'windows'. Adjust the _sourceCategory value to match your ingestion pipeline.
Data Sources
Required Tables
False Positives & Tuning
- Web-based SVG design platforms (e.g., Canva desktop app using embedded browser, browser-based Inkscape) that legitimately download SVG files and subsequently invoke local utilities for format conversion or export processing.
- Email security awareness training platforms (KnowBe4, Proofpoint Security Awareness) that deliver simulated phishing emails with SVG attachments to test detection coverage — analyst test machines will generate this alert intentionally.
- Browser-based CI/CD dashboards (GitHub Actions web UI, Jenkins) where clicking an artifact download link triggers a helper script via a browser extension or OS file handler association, creating a browser-parent + cmd-child process chain.
Other platforms for T1027.017
Testing Methodology
Validate this detection against 4 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 1Create and Open Malicious SVG with Embedded JavaScript
Expected signal: Sysmon Event ID 11: File Create — TargetFilename ending in Invoice-2024.svg written to Downloads directory by powershell.exe. Sysmon Event ID 1: Process Create — browser process (e.g., msedge.exe or chrome.exe) launched with the SVG file path as argument. Sysmon Event ID 3: Network Connection — may be generated if browser makes requests after opening file.
- Test 2SVG Smuggling with Blob URL Payload Download Simulation
Expected signal: Sysmon Event ID 11: File Create — document-viewer.svg written to Downloads by powershell.exe. If opened in browser: Sysmon Event ID 11 — browser may write document.exe to Downloads directory. Sysmon Event ID 1 — browser process launch with SVG path. Network telemetry: Blob URL creation stays local (no external network), but browser history records the file:// URI.
- Test 3SVG File Delivered via Email Simulation with Zone Identifier Check
Expected signal: Sysmon Event ID 11: File Create — Invoice_March2024.svg created in Outlook INetCache directory by powershell.exe. Sysmon Event ID 15 (FileCreateStreamHash): ADS Zone.Identifier written to the SVG file, indicating internet-sourced content (Zone=3). This ADS event is a strong indicator of an externally-sourced file.
- Test 4SVG Embedded in HTML File (HTML Smuggling Combination)
Expected signal: Sysmon Event ID 11: File Create — invoice-document.html written to Downloads by powershell.exe. Select-String output confirms presence of <svg>, <script>, atob, and blob indicators in the file. If opened in browser: potential Sysmon Event ID 11 for invoice.exe creation in Downloads.
References (10)
- https://attack.mitre.org/techniques/T1027/017/
- https://blog.talosintelligence.com/html-smugglers-turn-to-svg-images/
- https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/pixel-perfect-trap-the-surge-of-svg-borne-phishing-attacks/
- https://www.bleepingcomputer.com/news/security/phishing-emails-increasingly-use-svg-attachments-to-evade-detection/
- https://cofense.com/blog/svg-files-abused-in-emerging-campaigns/
- https://learn.microsoft.com/en-us/microsoft-365/security/defender-endpoint/advanced-hunting-devicefileevents-table
- https://learn.microsoft.com/en-us/microsoft-365/security/defender-endpoint/advanced-hunting-deviceprocessevents-table
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1027.006/T1027.006.md
- https://www.w3.org/TR/SVG2/interact.html#EventAttributes
- https://docs.splunk.com/Documentation/SplunkCloud/latest/SearchReference/CommonStatsFunctions
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