Ramnit — PDF malware analysis

Static analysis result for SHA-256 ccdd9b7d9ab2b134…

MALICIOUS

PDF

111.3 KB Created: 2016-10-31 14:21:23 +06:21 Authoring application: WPS Office
MD5: e1740048bc6af351183b0e261eb7c098 SHA-1: 5f26b7d07e1ead415f25a05040fd4a2beb9a4a73 SHA-256: ccdd9b7d9ab2b1342a64b7feca6efbcb43aca25f755259631d2699472f507699
212 Risk Score

Malware Insights

Ramnit · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution T1204.002 Malicious File T1105 Ingress Tool Transfer

The PDF contains an embedded VBScript that reconstructs and executes a PE payload named 'svchost.exe'. This payload was detected by ClamAV as Win.Trojan.Ramnit-9775455-0. The embedded script utilizes 'WScript.Shell' and 'Scripting.FileSystemObject' to achieve this, indicating a dropper functionality.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 4

  • VBScript in PDF stream reconstructs and runs a PE payload critical PDF_VBS_HEX_PE_DROPPER
    PDF stream contains an HTML/VBScript block that decodes a long hex string into a Windows executable and runs it via WScript.Shell. This is an embedded dropper payload, not ordinary PDF JavaScript.
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Embedded script payload in PDF stream high PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain script execution markers such as ActiveXObject/CreateObject, WScript.Shell, PowerShell, or shell-exec primitives. This is stronger than ordinary PDF JavaScript because it indicates a staged external script payload hidden in stream bytes.
  • Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_vbs_dropper_0000034d.vbs
50b36b292c4a29f5f0d9642bb1487d597e7f817cb538628ff0d791b00e4fac65
pdf-embedded-script PDF raw bytes VBScript dropper at offset 0x34D 113122 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s). Carved artifact contains 1 long base64-like blob(s).
svchost.exe
fd6c69c345f1e32924f0a5bb7393e191b393a78d58e2c6413b03ced7482f2320
embedded-pe Decoded PE from PDF VBScript dropper at offset 0x34D 56320 bytes
Detection
ClamAV: Win.Trojan.Ramnit-9775455-0
Obfuscation or payload: likely
Carved artifact entropy is 7.89, consistent with packed or encrypted content.