Ramnit — PDF malware analysis

Static analysis result for SHA-256 bda78545cb233e0c…

MALICIOUS

PDF

112.8 KB
MD5: 4a5594f4ed4c8625857f0654c9916187 SHA-1: b87dad95609602756ee38da8497876b78e2aa093 SHA-256: bda78545cb233e0c430b95f83ab6d63b09fac6e644b632be03b328c31d8938e4
180 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 reconstructs and executes a PE payload named 'svchost.exe'. This is further supported by ClamAV detection identifying the extracted artifact as Win.Trojan.Ramnit. The embedded script is responsible for dropping and executing the second-stage payload, which is a common technique for malware delivery.

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_00000980.vbs
50b36b292c4a29f5f0d9642bb1487d597e7f817cb538628ff0d791b00e4fac65
pdf-embedded-script PDF raw bytes VBScript dropper at offset 0x980 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 0x980 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.