Malicious PDF — malware analysis report

Static analysis result for SHA-256 1957994159114c9c…

MALICIOUS

PDF

111.2 KB
MD5: d3e458a5d476e740214893a3f90a91f3 SHA-1: fb810768bbf88adf8bb4bb30ddce9df094035daa SHA-256: 1957994159114c9c1cebf4c8b2e0f6ab5de1294343814e738bc487c23a72cd5f
210 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF contains embedded VBScript that reconstructs and executes a PE payload named 'svchost.exe'. This script is identified as a dropper for a PE file, which was further confirmed by ClamAV detecting it as Win.Trojan.Ramnit. The embedded script is responsible for dropping and executing the second-stage payload, indicating a typical downloader or dropper attack pattern.

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_000002f0.vbs
50b36b292c4a29f5f0d9642bb1487d597e7f817cb538628ff0d791b00e4fac65
pdf-embedded-script PDF raw bytes VBScript dropper at offset 0x2F0 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 0x2F0 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.