Malicious PDF — malware analysis report

Static analysis result for SHA-256 2acf1df5407e5fca…

MALICIOUS

PDF

16.0 KB
MD5: c2bee6e0cfea370623303dafca35c71e SHA-1: 9c210e818d664213738c42da11b17d13e0fbb6b8 SHA-256: 2acf1df5407e5fca2ca9f3fe309617501389d7f5ad6b282e8c8eb4d512a788e1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains obfuscated JavaScript, flagged by multiple heuristics as a dropper. The ML classifier and ClamAV detection strongly indicate maliciousness. The embedded JavaScript is designed to download and execute a second-stage payload, as evidenced by the 'PDF_JS_OBFUSCATED_DROPPER' heuristic and the presence of deobfuscated JavaScript files. The specific ClamAV detection name 'Pdf.Dropper.Agent-7243027-0' is included as a primary IOC.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • ClamAV: Pdf.Dropper.Agent-7243027-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7243027-0
  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 3 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_dashed_payload, repeated_pluginschk. This is strongly consistent with pre-2011 Adobe Reader PDF droppers — OpenAction JS reads encoded data from annotation subjects, decodes it through one or more hex / base-N loops, and invokes eval indirectly (method name built one character at a time). The actual CVE is hidden in the final decoded layer and is not visible via static analysis.
  • JavaScript action low 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.
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed stream)
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0005_000.js
a3319192cac6d4dc4eeb6af2d736b0ffec979b23116a003bc7c23382761c32a5
pdf-javascript-stream PDF /JS object 5 at offset 0x148 733 bytes
legacy_pdfkit_stage_000.js
79fed5cefbcc4475860c01f174d8d489c2946cf20472c47f3f5d3f4882f93aad
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1B5F 12734 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
b1942968166612eee15927a7268181c1e502bf7804454c1b89a598cfae4c2a71
deobfuscated-js PDF JavaScript deobfuscation pass 109758 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).