Malicious PDF — malware analysis report

Static analysis result for SHA-256 f3e7e632939d9fcd…

MALICIOUS

PDF

17.7 KB
MD5: 76cf0001a0c9dce9c922d7060e5e0699 SHA-1: 809a91a3ac20b6f82487a5dce5759f33cfd9e83b SHA-256: f3e7e632939d9fcdc3982405d3a01cb87d35aa6a57eb7ba4a4a70529a43df122
134 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains heavily obfuscated JavaScript, identified by heuristics such as 'PDF_JS_OBFUSCATED_DROPPER'. This script is designed to decode and execute further stages, likely downloading and running a secondary payload. The 'ClamAV: Pdf.Exploit.Agent-35901' detection further confirms its malicious nature. The obfuscated JavaScript and dropper behavior are characteristic of many PDF-based malware delivery mechanisms.

Heuristics 7

  • ClamAV: Pdf.Exploit.Agent-35901 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35901
  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 4 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, incremental_eval_build, 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.
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • 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_obj0009_000.js
4718a27c2224fc36bf24f8e8e04598f1ad78adce4401c7be2708318738a6983d
pdf-javascript-stream PDF /JS object 9 at offset 0x4426 469 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
fc8eedbbf685c326aa1d401d29c8764a2402062c5737f1ba820b781bddf62a1b
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1AC2 11530 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
1d67310a490dbd5f88e28ec8468d06e01bbcf9b045c565a5b572965f9f6b7e72
deobfuscated-js PDF JavaScript deobfuscation pass 104586 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).