Ramnit — PDF malware analysis

Static analysis result for SHA-256 e16101bc2a1f65dc…

MALICIOUS

PDF

110.7 KB
MD5: 36cc2bcbb330965d37c2cc81887a5e04 SHA-1: cda26629d6df53daac4d6d4276ecfe7d3bdfd3e2 SHA-256: e16101bc2a1f65dcb16c37c0d5af400838b3fb1fdbe4ceaebeb983c2f0e84ac0
212 Risk Score

Malware Insights

Ramnit · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

This PDF file contains an embedded VBScript that reconstructs and executes a PE payload named 'svchost.exe'. The VBScript utilizes 'Scripting.FileSystemObject' and 'WScript.Shell' to write and run the payload. ClamAV identified the extracted artifact as Win.Trojan.Ramnit, and ML classification strongly indicated maliciousness. The primary attack pattern involves dropping and executing a second-stage PE file.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9941

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_000000d4.vbs
50b36b292c4a29f5f0d9642bb1487d597e7f817cb538628ff0d791b00e4fac65
pdf-embedded-script PDF raw bytes VBScript dropper at offset 0xD4 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 0xD4 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.