Ramnit — PDF malware analysis

Static analysis result for SHA-256 971bbab541ffdf5a…

MALICIOUS

PDF

111.7 KB
MD5: d6a410d9664979a49eab7694eb908168 SHA-1: efb0d78396fd8fa8da87aa18eae395e1cece5633 SHA-256: 971bbab541ffdf5ac845595d0b6f8d252a9ddc0b00de157d89bbbbfd1f0da7fe
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 is designed to reconstruct and execute a PE payload. The script is identified as a dropper, and the dropped file is named 'svchost.exe'. ClamAV detection on the extracted artifact points to the Ramnit family. The ML classifier also flagged the PDF as malicious with a high score.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9695

Heuristics 5

  • 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.
  • PDF paints image(s) but contains no text operators info PDF_IMAGE_ONLY_LURE
    PDF has 1 image XObject(s) and the content stream contains no text-emitting operators (BT/ET, Tj, TJ, ', ") in either raw bytes or decompressed streams — this is the screenshot-as-PDF pattern used to bypass text-based scanners and to deliver instructions purely through rendered pixels. It is informational unless paired with invisible links or risky URI context.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_vbs_dropper_000004de.vbs
50b36b292c4a29f5f0d9642bb1487d597e7f817cb538628ff0d791b00e4fac65
pdf-embedded-script PDF raw bytes VBScript dropper at offset 0x4DE 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 0x4DE 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.