PDF malware analysis — malicious · 1703afc95a772b96

MALICIOUS

PDF

10.5 KB Created: 2010-07-15 23:02:38 +04:00 Authoring application: is4kxI (via e35d7a5)

MD5: cb940e8022ca0602aea596b6fb2c3c10 SHA-1: 0bf411932368a5ecd6f289de922dc39cd9af67b8 SHA-256: 1703afc95a772b96c1ceb00eecb96d4eec6f850dff0f168b96ea3631d0576dd5

124 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript that is heavily obfuscated using string concatenation and XOR encryption. The script appears to be designed to download and execute a second-stage payload, as indicated by the 'PDF JavaScript exploit cluster' heuristic and the ML classifier's high confidence score. The reconstructed XOR key 'uSMq' and the obfuscated data suggest a malicious intent to compromise the user's system.

Machine Learning

Nyx PDF Classifier malicious score 0.9998

Heuristics 6

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.
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.
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)
Optional Content Group with action trigger low PDF_OPTIONAL_CONTENT

Optional Content Group (layer) co-occurs with an action trigger — content can be selectively hidden from viewers or scanners while the action still fires on open
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 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0011_000.js` `57a713cbb9b922d2274e05a7f02578b8d45b20fc6f0cfe7316ea4a3a936e605d`	pdf-javascript-stream	PDF /JS object 11 at offset 0x2274	671 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`javascript_obj0013_001.js` `7b78efd4b8ba0cd6aa89bc96b802348b263d6d1cdeb42e714a9ce6a205bc8fdf`	pdf-javascript-stream	PDF /JS object 13 at offset 0x2425	49 bytes
`javascript_obj0015_002.js` `9f2778b3ab0d26cf6acbdf639a7ddc2413e7881c4dcc12fbf43225f1146fae7b`	pdf-javascript-stream	PDF /JS object 15 at offset 0x24CF	61 bytes

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