Malicious PDF — malware analysis report

Static analysis result for SHA-256 b750eeed7e036b08…

MALICIOUS

PDF

16.0 KB
MD5: a07bc2eb43ed19261ca4516c64bec83e SHA-1: 4c9fd19df29021a62fbb2dbff654bd5b11e7c8b8 SHA-256: b750eeed7e036b0853872e6640621f9506a0701709fba996b7fb438ff4877cec
96 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains obfuscated JavaScript, flagged as a high-confidence dropper. This script is designed to download and execute a second-stage payload, as indicated by the 'ML_NYX_PDF_MALICIOUS' heuristic and the presence of deobfuscated JavaScript files. The obfuscation techniques and multi-stage nature suggest a downloader designed to evade static analysis.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • 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
0fc6aaa130439388faea15fca2cc2cae8a4dd3bcfb8e0c96843c76897d9c3f2f
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1B46 12670 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
62b29d1e0f0594f29ffdc5d0a40bd95d4468e81e21a4c39685aec3ca1e1e0e8e
deobfuscated-js PDF JavaScript deobfuscation pass 64196 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).