PDF malware analysis — malicious · 52c9822b7fa68bff

MALICIOUS

PDF

9.2 KB

MD5: b4382f1c9e5d5cdd56377baca5db02bf SHA-1: 3399948740de58cb3f760ec4780f83c534e4e783 SHA-256: 52c9822b7fa68bffefd440b05765d9408dcc0614e4f2bca5c935e1d7cb3e0c07

266 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1059.007 JavaScript

The PDF document contains multiple embedded JavaScript streams, with critical heuristics indicating the use of eval() and unescape() for obfuscation. Specifically, the 'CVE_2007_5659' heuristic points to the exploitation of a known vulnerability via the Collab.collectEmailInfo method, using a hex-encoded stager. This stager likely decodes and executes further malicious JavaScript, which is a common technique for downloading and running secondary payloads. The presence of multiple large deobfuscated JavaScript files further supports this. No specific family could be identified.

Heuristics 9

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-35912 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-35912
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
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.
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_obj0007_000.js` `7218a1c68060953321573daa035b16f5f32928ce25a9eb656690dbe78cd9464e`	pdf-javascript-stream	PDF /JS object 7 at offset 0x19B	201 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`annotation_subject_callee_hex_stage_000.js` `94cd3c0c181bc00dce2e22945e9ecf662f12b44449aaec7f49785e76dccdb7d0`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x14A	5061 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_001.js` `ffe900481842e817ef5550006b995421f968b8cbc4df53453c54115ec5d836b4`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x2B5	11954 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).
`deobfuscated.js` `aacf0586d7ee0afa1a5a5beca8b0561d1ead2d576f9c599cca990de48d786f7a`	deobfuscated-js	PDF JavaScript deobfuscation pass	42242 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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