PDF malware analysis — malicious · 661f6c96a2dc60fb

MALICIOUS

PDF

26.2 KB Created: 2011-01-23 11:48:19 +02:00 Authoring application: Citi Student Loans (via mPDF 5.0)

MD5: c25241c61575c503a25bfe6434712164 SHA-1: ca21cd9a834ea30077a76f4919e8fcc291ce3641 SHA-256: 661f6c96a2dc60fbfeebf660dc7b5f0ea74e08e7a0a9b84b77d6bfb56a835efd

208 Risk Score

Malware Insights

MITRE ATT&CK

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

The PDF contains obfuscated JavaScript that utilizes the unescape function to decode a URL. This URL, 'http://searchglobalsite.com/in.cgi?11', is then used with getURL to redirect the user. This behavior is characteristic of a downloader or initial access vector, aiming to retrieve and execute further malicious content. The critical heuristic firing for 'PDF JavaScript exploit cluster' further supports this assessment.

Machine Learning

Nyx PDF Classifier malicious score 0.9995

Heuristics 7

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
Obfuscated document JavaScript getURL redirector high PDF_JS_OBFUSCATED_GETURL_REDIRECTOR

PDF document-level JavaScript automatically calls getURL() on an HTTP(S) destination hidden behind percent escapes. The decoded path is a redirector-style endpoint such as /in.cgi or /go.php. This is malicious routing behavior rather than a PDF parser CVE.
Suspicious extracted artifact medium 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.
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 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://searchglobalsite.com/in.cgi?11

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0020_000.js` `357d06d70777f397a54fd04180a5ee36f36a8ec5c7cbbafdfab41f20901b25ac`	pdf-javascript-stream	PDF /JS object 20 at offset 0x617F	136 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 hex-escaped blob(s).
`javascript_obj0020_001.js` `607a0753f2d28ea7a383d2e729ee9a1eeb69db22eafb74fa3e1d444ae047c123`	pdf-javascript-stream	PDF /JS object 20 at offset 0x617F	134 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 hex-escaped blob(s).

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