PDF malware analysis — malicious · a5c81080a3d35caf

MALICIOUS

PDF

15.4 KB

MD5: 1a78efc313ca01ebcbff730d39ba4fc1 SHA-1: aec4404f18ae785ce8566c4e5785f638bafd8485 SHA-256: a5c81080a3d35caf1179633934dfd00b26bdacf2c7392aae39670c0709653a63

204 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment T1204.001 Malicious Link

This PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, and a high-confidence PDF_EVAL call using unescape(). The ML classifier strongly flagged this as malicious. The embedded JavaScript file, 'javascript_obj0012_000.js', is suspicious and likely responsible for executing the malicious payload. The exact intent of the script is unclear due to obfuscation, but its presence in conjunction with exploit-related heuristics suggests it's designed to download and execute a second-stage payload.

Machine Learning

Nyx PDF Classifier malicious score 0.9997

Heuristics 10

CCITTFaxDecode + TIFF/XFA exploit prep — LibTIFF CVE-family indicator high CVE related PDF_CCITT_CVE_2010_0188_RELATED

PDF uses /CCITTFaxDecode together with TIFF/XFA exploit-preparation markers such as rawValue image-field assignment, TIFF data, or heap-spray JavaScript. This matches the delivery pattern for Adobe Reader LibTIFF/CCITTFax parser exploit families, including CVE-2010-0188, but does not prove the exact malformed TIFF primitive.
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX

Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
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.
XFA form low PDF_XFA

PDF uses XML Forms Architecture — can contain script logic
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)
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 http://ns.adobe.com/xdp/
- http://www.xfa.org/schema/xci/2.6/
- http://www.xfa.org/schema/xfa-template/2.6/

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0012_000.js` `09de78b7de291aa3ddc78e96475725267630bf326894c1fb6b9aff709f8aec31`	pdf-javascript-stream	PDF /JS object 12 at offset 0x1BF2	363 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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