Malicious PDF — malware analysis report

Static analysis result for SHA-256 87c7a86f664433d7…

MALICIOUS

PDF

43.4 KB
MD5: 1ae5de3b401e2d29071a2d7b56ee98ab SHA-1: 21b6e42fb30e5708c8f4ee31f1b40e126952161a SHA-256: 87c7a86f664433d7587d633afb373507ab426ceae52aa8919902a0d161f5d118
296 Risk Score

Malware Insights

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

The PDF sample contains multiple critical heuristic firings indicating exploitation of Adobe Reader U3D vulnerabilities (CVE-2009-3459 and CVE-2009-3953). Embedded JavaScript is present and obfuscated, designed to act as a dropper. The script attempts to retrieve a payload from annotation subjects and execute it, indicating a multi-stage attack designed to download and run additional malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • Adobe Reader U3D auto-activated 3D annotation — CVE-2009-3459 critical CVE likely CVE_2009_3459_U3D_AUTOACTIVATE
    PDF contains a /Subtype /3D annotation that is configured to auto-activate on page view (/3DA <</A /PV /AIS /I>>) alongside a /U3D stream and JavaScript. This is the document shape used by CVE-2009-3459 (Adobe Reader U3D CLODProgressiveMeshDeclaration heap overflow, APSB09-15): the U3D parser runs without any user interaction once the page is rendered, while the accompanying JavaScript prepares a heap-spray to land controlled memory inside the corrupted allocation.
  • Adobe Reader U3D CLODProgressiveMeshDeclaration exploit critical CVE likely CVE_2009_3953
    PDF combines malformed U3D 3D content with JavaScript/action activation. CVE-2009-3953 is an Adobe Reader/Acrobat U3D CLODProgressiveMeshDeclaration array-boundary vulnerability triggered by malformed U3D data in a PDF.
  • 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.
  • 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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0005_000.js
a3319192cac6d4dc4eeb6af2d736b0ffec979b23116a003bc7c23382761c32a5
pdf-javascript-stream PDF /JS object 5 at offset 0x14F 733 bytes
generic_stage_recovery_000.js
d0d9b30997e09d7380aa1f50db3a2ef0c80cafe011beab0224533da2964e68f5
deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 5 at offset 0x14F 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
f0f9d3c6bcee7c81ebb146fc92fea73b5312b3101557ca59a3ea336184486385
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1BF6 13175 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
7b4c39decb628e41f5942675f8e58c05cf04c7d425a4a787c3fccedc84518805
deobfuscated-js PDF JavaScript deobfuscation pass 292591 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
u3d_00_off00004152.bin
fb27c6f6ffe2b08a88f79f344ef3cb4f85460ac81a062194b6fd84ab6e48b628
pdf-3d-stream PDF U3D 3D stream at offset 0x4152 28021 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.79, consistent with packed or encrypted content.