Ramnit — PDF malware analysis

Static analysis result for SHA-256 457d0870d8c1edfd…

MALICIOUS

PDF

111.1 KB
MD5: b12524de4a47490cc8a1da55af59e224 SHA-1: 017871193b3a2c1e051f07a8b17aea7fd4159ff0 SHA-256: 457d0870d8c1edfd13dc0f407297e462bde85b942ef7436ede23475bd9564857
210 Risk Score

Malware Insights

Ramnit · confidence 95%

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

The PDF file contains an embedded VBScript that is designed to reconstruct and execute a PE payload. The script utilizes 'Scripting.FileSystemObject' and 'WScript.Shell' to write and run the payload, which is identified as 'svchost.exe'. This behavior is consistent with malware delivery mechanisms, and the extracted artifact was detected as Win.Trojan.Ramnit. The embedded VBScript is the primary mechanism for executing the malicious payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9989

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_000002b1.vbs
50b36b292c4a29f5f0d9642bb1487d597e7f817cb538628ff0d791b00e4fac65
pdf-embedded-script PDF raw bytes VBScript dropper at offset 0x2B1 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 0x2B1 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.