Malicious PDF — malware analysis report

Static analysis result for SHA-256 1cbe56d2986a0950…

MALICIOUS

PDF

15.6 KB
MD5: 51738ba91cf65328229c0dd793a32e36 SHA-1: 470faaba1c9dc4969d293fdd55fb4ed10d86dc5e SHA-256: 1cbe56d2986a0950c8be0c045a1be1ee089f50f31e59bcc0f6919bce6fa25e77
126 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains obfuscated JavaScript, identified as a multi-stage dropper. The heuristics indicate that the script is designed to download and execute a second-stage payload. The ClamAV detection further confirms its malicious nature as Pdf.Dropper.Agent-7236169-0. The obfuscated nature of the script and the presence of anti-analysis checks suggest a deliberate attempt to evade detection.

Heuristics 6

  • ClamAV: Pdf.Dropper.Agent-7236169-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7236169-0
  • 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
60b1229c4f779e4219adc254cef782b752a658e914b87b017bb04965fc001478
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1AB6 12319 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
dc0329bfd3494dd0d093e0ccbba8389a537d68a6cbdcba6284e8424aa52401ba
deobfuscated-js PDF JavaScript deobfuscation pass 60551 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).