PDF malware analysis — malicious · 285171621d8fe967

MALICIOUS

PDF

7.8 KB

MD5: f644869d87cb5eedc61e6abf8618ed29 SHA-1: 1a8e7b10ece46d47d81c43bcd0dc1a63a8afcfc0 SHA-256: 285171621d8fe967069bf0da9823de430b65bebbc879460ceee19aeab258a8b9

134 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

The PDF file contains obfuscated JavaScript, identified by heuristics like PDF_JAVASCRIPT and PDF_JS_OBFUSCATED_DROPPER. The critical CVE_2007_5659 heuristic indicates exploitation of this vulnerability via the Collab.collectEmailInfo function to decode and execute a JavaScript payload. The presence of multiple deobfuscated JavaScript files suggests a multi-stage infection process, where the initial PDF dropper likely downloads and executes additional malicious content. The exact URLs or final payloads were not directly extracted, limiting the IOCs to the identified vulnerability.

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)
Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER

PDF JavaScript shows 3 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_dashed_payload, 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` `9d5c7e01faed5b04e9ec11f1d98b73f0012c871beaf60e9f9d32ad6df00d46f7`	pdf-javascript-stream	PDF /JS object 5 at offset 0x148	550 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_000.js` `322a77610ee0201661bfa0807e552aff2ed1cbe498419b1a4c125bcf3663556f`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x19FA	1910 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` `0ef62ff4b5e573e96b7659eaf8e4a7c97dde1caf8f849fd46243be09074c6543`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x359	4759 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`deobfuscated.js` `21da2f4208f894f4a8926e72216aa644e18bae3661f9ee5455934107c8fe8e36`	deobfuscated-js	PDF JavaScript deobfuscation pass	38179 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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