PDF malware analysis — malicious · 540f5bb87b72ad39

MALICIOUS

PDF

11.7 KB

MD5: 2100c3c38142c9ff95755ac3b41a57b6 SHA-1: a03ce5a539b6e9eb70879be22cd4542b04183867 SHA-256: 540f5bb87b72ad3994052fb3ce151f5f6f9c0f849726d50f8c6ba708075b55ea

186 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.001 Malicious Link T1204.002 Malicious File

The PDF file contains embedded JavaScript that is heavily obfuscated and uses String.fromCharCode. The critical heuristic CVE_2007_5659 indicates the exploitation of this vulnerability via the Collab.collectEmailInfo method. The JavaScript is decoded and evaluated, likely to download and execute a second-stage payload. The ClamAV detection further confirms its malicious nature.

Heuristics 7

Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659

PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
ClamAV: Pdf.Exploit.Agent-36088 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-36088
Annotation subject callee-key hex JavaScript stager high PDF_ANNOT_SUBJECT_CALLEE_HEX_STAGER

PDF JavaScript uses syncAnnotScan()/getAnnots() to read an indirect annotation /Subject stream, percent-decodes it through marker replacement, then uses a callee.toString()-derived key to decode and eval the final exploit stage.
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)
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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0007_000.js` `9fd87306e37a04c361ea1b68a1cf4474b7a018e2270929a8c382cd129d8fc406`	pdf-javascript-stream	PDF /JS object 7 at offset 0x19C	566 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`annotation_subject_callee_hex_stage_000.js` `626e58d66a9733f34b6bb0971a0d8d0141f3c02bc12b75a77d7d0360e7796618`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x14A	5187 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).

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