Malicious PDF — malware analysis report

Static analysis result for SHA-256 df5e32efcda320b6…

MALICIOUS

PDF

43.3 KB
MD5: dd86b92fe96c3b04a01f927e8e5e8d61 SHA-1: 689b30ecb246a781b11c93316b0f7cce9c06f445 SHA-256: df5e32efcda320b64b1e5ba75cf15e4ed58885045a22175860ae536748652d17
136 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF contains obfuscated JavaScript, flagged as a high-confidence dropper. This script is designed to download and execute a second-stage payload, indicated by the 'PDF_JS_OBFUSCATED_DROPPER' heuristic. The presence of U3D content and embedded JavaScript streams further supports its malicious nature. The extracted artifacts 'deobfuscated.js', 'legacy_pdfkit_stage_000.js', and 'u3d_00_off0000411e.bin' are likely components of this multi-stage attack.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • U3D/3D content in PDF — Adobe Reader 3D parser CVE-family indicator high CVE related PDF_U3D_CVE_RELATED
    PDF contains U3D (Universal 3D) or 3D annotation content — CVE-2011-2462 and CVE-2009-3953 are critical vulnerabilities in Adobe Reader's U3D processing that allow arbitrary code execution. U3D content in PDFs is extremely rare in normal documents.
  • 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
1fe3d16c29139eff72916526fa791c682580a9a486b6df1feb1daaf942866d89
pdf-javascript-stream PDF /JS object 5 at offset 0x14F 711 bytes
legacy_pdfkit_stage_000.js
33d767dd05dab524a23051ed596824d0fd79e3065f8d3351429e6b0b37919872
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1C13 12429 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
45ca27bb348cfc65e826b2dbcfb86846eb5d5c0db5ada7aa0651b1f99b7eb4a5
deobfuscated-js PDF JavaScript deobfuscation pass 207458 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
u3d_00_off0000411e.bin
fb27c6f6ffe2b08a88f79f344ef3cb4f85460ac81a062194b6fd84ab6e48b628
pdf-3d-stream PDF U3D 3D stream at offset 0x411E 28021 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.79, consistent with packed or encrypted content.