PDF malware analysis — malicious · 2390a59da0b7afcf

MALICIOUS

PDF

8.3 KB

MD5: 85a1b599b8c82eba15d158fc5d2caf0e SHA-1: 0156a8cfdc7e1339da3526180b4ea785a63506c3 SHA-256: 2390a59da0b7afcf8a0fe2efb2314ca63684f86fd1d3d294259dcd43c63b4dbb

134 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript/JScript T1204.002 Malicious File: User Execution: Malicious Script

The PDF sample contains obfuscated JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT', 'PDF_JS_OBFUSCATED_DROPPER', and 'CVE_2007_5659'. The script is designed to exploit a known PDF vulnerability (CVE-2007-5659) to download and execute a second-stage payload. The presence of multiple deobfuscated JavaScript files suggests a multi-stage infection chain.

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` `b35c9ab50722c88cfe9bbf5393c4efe42f3f3be9de48c86c11696ee43ba3b82e`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1BF0	1800 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` `c3a2caf67eaa2eed4e38bc4da130f7745e2a8da0bceb3b0d642d3344bdb6b5f1`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x359	5178 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`deobfuscated.js` `eb7e340729cb2e8c99becfb8165a06b5408cb516974b37a75024be6f741aaee1`	deobfuscated-js	PDF JavaScript deobfuscation pass	22884 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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