SamSam ransomware technical analysis and IOCs
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CISA releases technical analysis of SamSam .NET ransomware variant with file hashes, encryption mechanics, and C2 infrastructure.
This CISA Malware Analysis Report (MAR) provides detailed technical documentation of SamSam ransomware, a .NET-based variant targeting Windows systems. The report includes reverse-engineered analysis of the encryption mechanism: victims' files are encrypted using AES-256 in CBC mode with randomly generated keys, which are then encrypted with an RSA public key embedded in the malware. The malware avoids encrypting system files and specific directories, and kills any running SQL processes before encryption. The ransom note references a Tor-based payment site and Bitcoin address for ransom demands.
The analysis covers six malware components including the main ss2.exe ransomware executable, a dropper, batch script, and supporting DLLs. The report provides SHA-256 hashes, hardcoded cryptographic keys used for the ransom note, and operational details such as command-line arguments and the .stubbin encrypted data format. The Tor onion domain jcmi5n4c3mvgtyt5.onion appears in the ransom note as the attacker's communication point. This is primarily informational analysis of a known ransomware family with no indication of active exploitation waves at the time of publication.
Mentioned in this report
Detection guidance
Taskkill Forcibly Terminating SQL Server Processes
taskkill.exe terminating SQL-named processes by image name, a pre-encryption step used by SamSam and other ransomware to release database file locks. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.
title: Taskkill Forcibly Terminating SQL Server Processes
description: Detects taskkill.exe invoked against SQL-related image names (sqlservr,
sqlagent, sqlwriter and similar). SamSam kills running SQL processes before encrypting
so database files are unlocked. Generalises on the taskkill /im plus sql pattern,
not on a specific binary name.
tags:
- attack.impact
- attack.t1486
logsource:
category: process_creation
product: windows
detection:
selection:
Image|endswith: \taskkill.exe
CommandLine|windash|contains|all:
- -im
- sql
filter_admin_tools:
ParentImage|endswith:
- \msiexec.exe
- \setup.exe
condition: selection and not filter_admin_tools
falsepositives:
- Database administrators or maintenance scripts restarting a hung SQL Server instance
- Software installers or upgrade scripts that stop SQL services before patching
level: medium
id: b4023f44-4f38-5084-885d-5e625f06ad8c
status: experimental
author: Vorant
references:
- https://www.cisa.gov/news-events/analysis-reports/ar18-337b
Creation of .stubbin Encrypted Data Files
File creation with the .stubbin extension, the encrypted data format reported for SamSam ransomware components. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.
title: Creation of .stubbin Encrypted Data Files
description: Detects file creation with the .stubbin extension. The SamSam analysis
describes a .stubbin encrypted data format used to hold encrypted payload or key
material. The extension is not used by common legitimate software.
tags:
- attack.impact
- attack.t1486
- attack.stealth
- attack.t1027
logsource:
category: file_event
product: windows
detection:
selection:
TargetFilename|endswith: .stubbin
condition: selection
falsepositives:
- Unrelated software that happens to use a .stubbin extension for its own data files
level: medium
id: 05ac29b4-4091-53cb-b636-d834ca651d70
status: experimental
author: Vorant
references:
- https://www.cisa.gov/news-events/analysis-reports/ar18-337b
1 more detection for this report is in the app — the rules that match its indicators, plus the Sigma rules already converted to Splunk SPL, to Elastic where their fields map onto Elastic's integrations and to Microsoft Defender XDR KQL wherever Defender records the activity, and the YARA and Suricata. Three days of it free, no card.
Behavioural rules are generated from public reporting — validate in your environment before deploying.
Source reporting: https://www.cisa.gov/news-events/analysis-reports/ar18-337b
What this brief leaves out
This page is the free tier: the write-up, the severity, the names. In the app the same report carries its extracted indicators, its detections (Splunk SPL already written, plus Elastic and Microsoft KQL where they apply), the actors and CVEs it names as live profiles, and the vendor research on the same campaign — the primary source the news paraphrased, cited and read directly.
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