PDF malware analysis — malicious · 5ea7a724d99fab3f

MALICIOUS

PDF

703.9 KB Created: 2021-05-06 22:42:29

MD5: df2ea74328ad43c4225cb6c8aa56f340 SHA-1: 6d2676711e19b6f5565f873420fe8e1d9a39d005 SHA-256: 5ea7a724d99fab3f05f50dccd57db59451334ac8640c532d426df319dad55c9e

230 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF sample contains embedded JavaScript that leverages the CVE-2020-9715 vulnerability. The JavaScript code appears to be designed to manipulate memory and potentially load external code, indicated by the use of functions like `unescape()` and `String.fromCharCode()`, and the explicit mention of `kernel32.dll` and `VirtualProtect` in the script. This strongly suggests the PDF is a dropper for a secondary malicious payload.

Machine Learning

Nyx PDF Classifier malicious score 0.9681

Heuristics 11

dataObjects ESObject stale-cache trigger — CVE-2020-9715 critical CVE exact CVE_2020_9715

PDF embeds a file and JavaScript follows the CVE-2020-9715 ESObject use-after-free trigger shape: access this.dataObjects[], clear the dataObjects entry, schedule app.setTimeOut(), then re-access the Data ESObject through toString().
PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER

PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
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.
Embedded file low PDF_EMBEDDED

PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
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)
External URI info PDF_URI

PDF contains an external URL action
Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL

The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
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.
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
URL https://adobereview.uservoice.com/
- http://www.w3.org/1999/02/22-rdf-syntax-ns#
- http://ns.adobe.com/xap/1.0/
- http://ns.adobe.com/xap/1.0/mm/
- http://purl.org/dc/elements/1.1/
- http://ns.adobe.com/pdf/1.3/
- http://ns.adobe.com/pdfx/1.3/

Extracted artifacts 9

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0508_000.js` `c4a8060e2a254739a0951ff988785c715482042a379cf09b2a10399e94c85489`	pdf-javascript-stream	PDF /JS object 508 at offset 0xA870F	10795 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s).
`javascript_obj0530_001.js` `8433dca28e2ce9876e690a6c9e5b9bbec7c8d08198b5135ae6f8b7552dfa63f6`	pdf-javascript-stream	PDF /JS object 530 at offset 0xAABB0	6340 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s).
`stream_016_off000070d7.bin` `c11cb8cfdf0f17b6f5f697110384d8318aa875573e0209135047cab5cb5dca38`	decompressed-pdf-stream	PDF FlateDecoded stream at offset 0x70D7	1833651 bytes
`stream_020_off000328bf.bin` `893a859eca5401895aec6b5e6246124430c51c09df8f8b7ec9aedf153bddbac4`	decompressed-pdf-stream	PDF FlateDecoded stream at offset 0x328BF	1491369 bytes
`stream_026_off00068651.bin` `517710f00acc02ea3199ee20575c9310eb66683b3ba6e3533125ef3de44bc024`	decompressed-pdf-stream	PDF FlateDecoded stream at offset 0x68651	1102248 bytes
`stream_029_off00077fc9.bin` `104d79a0db2565b1a19b2bc4e2f555d6d5f747d810412824404093e84b169adf`	decompressed-pdf-stream	PDF FlateDecoded stream at offset 0x77FC9	154368 bytes
`stream_068_off000ae67e.bin` `72ea876d00e7a8e23d5d2d0d87a9a94a589bbd26af7df5bc778a42cf2b3a9bb5`	decompressed-pdf-stream	PDF FlateDecoded stream at offset 0xAE67E	15612 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 6 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`font_00_cff_off00088e65.bin` `48350d8ae3f4c835da67d173692f7f7b37cd7562c161a07612770888056393f5`	pdf-font-stream	PDF embedded font (cff) at offset 0x88E65	7926 bytes
`font_01_cff_off0008a7ed.bin` `7fd9973dee0fb1d775fc88c42aa4d0066f3d843e6d95097419c6e27cae457647`	pdf-font-stream	PDF embedded font (cff) at offset 0x8A7ED	2332 bytes

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