PDF malware analysis — malicious · 5b52c65c218879f5

MALICIOUS

PDF

11.9 KB

MD5: c78817118fe8f68d6aa2560d7881bb6e SHA-1: 3c5db70b05538ec230f318d3066a881e4a908d1e SHA-256: 5b52c65c218879f54e31b77fb973e92dfa2e352db4fb4cff149f60cf18c82948

338 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF contains embedded JavaScript that leverages the CVE-2007-5659 vulnerability via the `syncAnnotScan` and `getAnnots` methods. This script is designed to decode and execute a payload. The critical heuristic `PDF_JS_SHELLCODE_DOWNLOAD_URL` indicates that the script contains a URL, `http://aghgiqfathr.com/nte/avorp1indep8%20.asp/eU230d9c2eH3e9b5fecV0100f060006R7fb2c620102T4e5ca501203l000cK1d2e4bec`, which is likely used to download and execute a second-stage payload. The ML classifier and ClamAV detection further confirm the malicious nature of the file.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 11

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.
ClamAV: Pdf.Exploit.Agent-36063 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-36063
Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY

Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
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://aghgiqfathr.com/nte/avorp1indep8%20.asp/eU230d9c2eH3e9b5fecV0100f060006R7fb2c620102T4e5ca501203l000cK1d2e4bec

Extracted artifacts 5

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0007_000.js` `eb39e2de4dbbc100de6d3e30aa43ff78fa075618862ba1ebba5151ea3a3b848d`	pdf-javascript-stream	PDF /JS object 7 at offset 0x19D	273 bytes
`generic_stage_recovery_000.js` `41323bb0bc5d6e8e4f59ad32a6e5f405b8b479252ecf9b61a0159542b2003e8e`	deobfuscated-js	generic stage recovery split-literal-normalize from JavaScript object 7 at offset 0x19D	263 bytes
`annotation_subject_callee_hex_stage_000.js` `1e4279760545365d87f0db9d320c0db349e1773b8ac5bf3e83b16cde105f7413`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x14A	5078 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` `552b82e4a5cbf9f791dc685cf149948c4fddf0e5939215cd04d44fa70aa57f56`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x2D6	12005 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`deobfuscated.js` `de1454c7c949d9b96c94a634adcccfc63f514afcfd7e12727ac67581a8e851e9`	deobfuscated-js	PDF JavaScript deobfuscation pass	81013 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).

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