PDF malware analysis — malicious · d72c7d337b8780fb

MALICIOUS

PDF

7.9 KB

MD5: f7628ce4008a4da9a48f7ad57cc52e02 SHA-1: b23996a0f5215cb2496eec002e13b8dac952f872 SHA-256: d72c7d337b8780fb6325b4a334375974e5b24fa3f8e859842fabc5b5a1d09f03

194 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.001 Malicious Link T1071.001 Web Protocols

The PDF file contains obfuscated JavaScript that exploits CVE-2007-5659 via the Collab.collectEmailInfo method. The script is designed as a multi-stage dropper, utilizing String.fromCharCode and hex decoding to deobfuscate and execute further stages. The primary intent appears to be downloading and executing a second-stage payload from a remote source, as indicated by the dropper's structure and the presence of embedded URLs.

Heuristics 8

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-35916 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-35916
Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER

PDF JavaScript shows 5 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, hex_dashed_payload, incremental_eval_build, repeated_pluginschk. This is strongly consistent with pre-2011 Adobe Reader PDF droppers — OpenAction JS reads encoded data from annotation subjects, decodes it through one or more hex / base-N loops, and invokes eval indirectly (method name built one character at a time). The actual CVE is hidden in the final decoded layer and is not visible via static analysis.
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)
syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN

PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed 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 4

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0005_000.js` `6c41320119e160dc719997b9a2efb3600ea9d7e9d7e44b4dc2125762dc9f365f`	pdf-javascript-stream	PDF /JS object 5 at offset 0x148	505 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_000.js` `dacfd3b0d4d35a079d10061a7a8265461b5a1290359d873d8c772e4306b37e12`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1A51	1733 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_001.js` `325c39c289a0e5db3099463362de95c17ec11f02cd1522691b7bcd052636fca9`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x352	4866 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s).
`deobfuscated.js` `0ab206305e5b08ae4423d0757719e8529a04043b767433e5f62c06fe08a5ced2`	deobfuscated-js	PDF JavaScript deobfuscation pass	26468 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 7 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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