Ramnit PDF malware analysis — malicious · b1c4845bcd609add

MALICIOUS

PDF

111.8 KB

MD5: fd2d255fa6a3ce2682283e80d7b13865 SHA-1: 8cfbdf4c8670d249cc2f6bc80e3b244281cb2f6f SHA-256: b1c4845bcd609adda7dc5e3e91703758f1e6f2bfbad69d8ff30d210e28d1c457

210 Risk Score

Malware Insights

Ramnit · confidence 95%

MITRE ATT&CK

T1059.005 Visual Basic 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 script leverages 'Scripting.FileSystemObject' and 'WScript.Shell' to drop and run the payload. ClamAV detection identifies the extracted artifact as Win.Trojan.Ramnit, and the ML classifier strongly indicates maliciousness. The embedded PE file is likely the second-stage payload.

Machine Learning

Nyx PDF Classifier malicious score 0.9986

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.

Filename	Kind	Source	Size
`embedded_vbs_dropper_00000564.vbs` `50b36b292c4a29f5f0d9642bb1487d597e7f817cb538628ff0d791b00e4fac65`	pdf-embedded-script	PDF raw bytes VBScript dropper at offset 0x564	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 0x564	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.

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