PDF malware analysis — malicious · 5efbb575974d450a

MALICIOUS

PDF

8.9 KB

MD5: 54694b2e0c5af5756b6f934febcc7ee7 SHA-1: 4b27cbd76f3dcfebc121375d3340d0cf30dccc51 SHA-256: 5efbb575974d450aebcbbd448c6146451db567d19a8fae234414002f512dc16d

498 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF contains JavaScript that leverages CVE-2007-5659 (Collab.collectEmailInfo) to execute arbitrary code. The embedded JavaScript decodes and evaluates a payload that contains a URL, http://ajnuocfdrukv.com/nte/TREST1.exe/eH1206abd8V0100f060006R5cf50aa8102Te493ad28201l0019K723c281f, which is used to download a second-stage executable. The use of eval() and unescape() functions, along with the specific exploit cluster, strongly indicates malicious intent.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 14

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)
Adobe Reader APSB08-13 patch-range version gate (CVE-2007-5659) high CVE likely PDF_JS_ADOBE_APSB08_13_PATCH_GATE

PDF JavaScript gates the exploit payload on (>= 8 && < 8.1.1) OR (< 7.1) — the Reader 7.0.x / 8.0–8.1.1 window patched by Adobe APSB08-13 for the CVE-2007-5659 Collab.collectEmailInfo buffer overflow. Only kits that target that exact bug check both of those patch points; benign scripts do not.
PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER

PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
Annotation subject percent-decoding eval stager critical PDF_ANNOT_SUBJECT_MARKER_EVAL_STAGER

OpenAction JavaScript forces annotation enumeration, reads an annotation /Subject payload with getAnnots(), rewrites marker bytes into percent escapes, decodes it with unescape(), and dispatches it through eval. This is a high-confidence exploit-kit staging pattern. It is intentionally not mapped to CVE-2009-1492 unless getAnnots() itself carries the crafted integer or long argument shape for that vulnerability.
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.
PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL

Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
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.
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.

URL http://ajnuocfdrukv.com/nte/TREST1.exe/eH1206abd8V0100f060006R5cf50aa8102Te493ad28201l0019K723c281f

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` `5b125d01dbbf09e0d7a442a6044319e9e6fe56eca0bc263c806252b45ed81148`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x14A	4952 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` `a559778d7cad23be8589f5a1d870d9b6b3f41e96a7cfe73a8fc5ca54de98e33f`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x2B5	11688 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` `fa2f8bcd0260352dd46db1c181114b071f6c8191ec1edd0c9b7bd8fd883f94b1`	deobfuscated-js	PDF JavaScript deobfuscation pass	39958 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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