Detect Standard Encoding in IBM QRadar
Adversaries may encode data with a standard data encoding system to make the content of command and control traffic more difficult to detect. Command and control (C2) information can be encoded using a standard data encoding system that adheres to existing protocol specifications. Common data encoding schemes include ASCII, Unicode, hexadecimal, Base64, and MIME. Some data encoding systems may also result in data compression, such as gzip. Malware families including SideTwist, Fysbis, Latrodectus, SeaDuke, Chaes, and Flagpro have all used Base64-encoded C2 traffic, making this one of the most prevalent C2 obfuscation techniques observed in the wild.
MITRE ATT&CK
- Tactic
- Command and Control
- Technique
- T1132 Data Encoding
- Sub-technique
- T1132.001 Standard Encoding
- Canonical reference
- https://attack.mitre.org/techniques/T1132/001/
QRadar Detection Query
SELECT
DATEFORMAT(starttime, 'yyyy-MM-dd HH:mm:ss') AS "Event Time",
sourceip AS "Source IP",
username AS "Username",
LOGSOURCENAME(logsourceid) AS "Log Source",
QIDNAME(qid) AS "Event Name",
"Process Name" AS "Process",
"Command Line" AS "Command Line",
"Parent Process Name" AS "Parent Process"
FROM events
WHERE
CATEGORYNAME(category) IN ('Process Creation', 'Audit Process Creation', 'OS Changes')
AND (
LOWER("Command Line") ILIKE '%frombase64string%'
OR LOWER("Command Line") ILIKE '%tobase64string%'
OR LOWER("Command Line") ILIKE '%base64 -d%'
OR LOWER("Command Line") ILIKE '%base64 --decode%'
OR LOWER("Command Line") ILIKE '%-encodedcommand%'
OR (
LOWER("Process Name") ILIKE '%certutil%'
AND (
LOWER("Command Line") ILIKE '%-decode%'
OR LOWER("Command Line") ILIKE '%/decode%'
OR LOWER("Command Line") ILIKE '%-urlcache%'
OR LOWER("Command Line") ILIKE '%/urlcache%'
OR LOWER("Command Line") ILIKE '%-encode%'
OR LOWER("Command Line") ILIKE '%/encode%'
)
)
OR (
LOWER("Process Name") ILIKE '%powershell%'
AND (
LOWER("Command Line") ILIKE '%-enc %'
OR LOWER("Command Line") ILIKE '%-ec %'
)
)
)
LAST 24 HOURS
ORDER BY starttime DESCIBM QRadar AQL detection for T1132.001 Standard Encoding C2 querying process creation events across Windows Security (EventID 4688) and Sysmon (Event 1) DSMs. Matches certutil LOLBin encoding abuse, PowerShell -enc/-ec short-form encoded commands, and explicit Base64 conversion calls. Requires 'Process Name' and 'Command Line' custom properties to be configured and extracted by the Windows Security or Sysmon DSM extension in your QRadar deployment.
Data Sources
Required Tables
False Positives & Tuning
- PKI administrators running certutil.exe for certificate encoding, trust store updates, or BITS job creation as part of normal Windows PKI infrastructure operations
- Enterprise endpoint management solutions (MECM/SCCM, BigFix, Tanium) delivering PowerShell management scripts using -enc to ensure safe cross-platform delivery of complex configuration payloads
- Developer workstations running build tools or test runners that use Base64-encoded embedded resources or configuration values in MSBuild task invocations or CI agent scripts
Other platforms for T1132.001
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 1PowerShell Base64 Encode and Decode Round-Trip
Expected signal: Sysmon Event ID 1: Process Create with CommandLine containing 'ToBase64String', 'FromBase64String', and 'IEX'. PowerShell ScriptBlock Log Event ID 4104 will capture the decoded content 'hostname; whoami'. Security Event ID 4688 (if command line auditing enabled) with full command line.
- Test 2certutil Base64 Decode to File
Expected signal: Sysmon Event ID 1: Process Create with Image=certutil.exe, CommandLine containing '-decode' and file paths. Sysmon Event ID 11: File Create events for both %TEMP%\encoded.b64 and %TEMP%\decoded.txt. Security Event ID 4688 with certutil command line (if auditing enabled).
- Test 3Base64 Encoded C2 Beacon Simulation via PowerShell
Expected signal: Sysmon Event ID 1: Process Create with CommandLine containing 'ToBase64String', 'Net.WebClient', and 'UploadString'. Sysmon Event ID 3: Network Connection attempt to 127.0.0.1:8888 (will fail — no listener). PowerShell ScriptBlock Log Event ID 4104 capturing the full encoding + upload script.
- Test 4Linux Base64 C2 Exfil Simulation via curl
Expected signal: Linux auditd or Sysmon for Linux: process creation events for 'base64' and 'curl' with command line arguments. Syslog: process execution entries. Network: outbound connection attempt to 127.0.0.1:9999 from curl.
References (9)
- https://attack.mitre.org/techniques/T1132/001/
- https://en.wikipedia.org/wiki/Binary-to-text_encoding
- https://en.wikipedia.org/wiki/Base64
- https://learn.microsoft.com/en-us/defender-endpoint/advanced-hunting-deviceprocessevents-table
- https://learn.microsoft.com/en-us/sysinternals/downloads/sysmon
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1132.001/T1132.001.md
- https://research.checkpoint.com/2021/irans-apt34-returns-with-an-updated-arsenal/
- https://www.elastic.co/security-labs/spring-cleaning-with-latrodectus
- https://www.zscaler.com/blogs/security-research/lyceum-net-dns-backdoor
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