Malicious PDF — malware analysis report

Static analysis result for SHA-256 07b0c31e1539ed2f…

MALICIOUS

PDF

16.5 KB
MD5: ea98401e95b7773c22841b4cf10d1179 SHA-1: 9f55c202aed564963017cb76791758bef787853c SHA-256: 07b0c31e1539ed2fdd940af7e736760b5c40e1713ef9ab172e92590f4267f292
196 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains obfuscated JavaScript, identified as a dropper, which attempts to evade analysis by checking the number of plugins. The script reconstructs a payload from annotation subjects and executes it, indicating a multi-stage attack. This behavior is consistent with a malicious PDF designed to deliver further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • ClamAV: Pdf.Dropper.Agent-7225395-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7225395-0
  • Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY
    Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
  • 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 4

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
generic_stage_recovery_000.js
d0d9b30997e09d7380aa1f50db3a2ef0c80cafe011beab0224533da2964e68f5
deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 5 at offset 0x148 717 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
58d249d3bdffda45af5fb608cfb445bd3770fb105d1f05354ac02b486f100bf8
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1C2F 13007 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
5217ea8a07620daef3276de22677352421a864abed835f1f7bfb4bf0a709d90e
deobfuscated-js PDF JavaScript deobfuscation pass 64512 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).