PDF malware analysis — malicious · 5cebf9a660aa6585

MALICIOUS

PDF

9.6 KB

MD5: c92b1e22a0970155ba43e500bbf950d5 SHA-1: 7b0c950c8fdd12a863ecf71ecbc83130b535c323 SHA-256: 5cebf9a660aa6585cdc318b78e0b60c32b2edd1f25ef46327c5f8ce957038ea8

278 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The sample is a PDF file that leverages JavaScript to exploit CVE-2007-5659. The embedded JavaScript is designed to download and execute a second-stage payload from the URL http://fejxwacusgxx.com/nte/AVORP1TUTA8.html/eU230d9c2eH0c946ee5V0100f060006R00000000102Td44f1165203l000cK87393418. This indicates a downloader or dropper functionality.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 10

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.
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://fejxwacusgxx.com/nte/AVORP1TUTA8.html/eU230d9c2eH0c946ee5V0100f060006R00000000102Td44f1165203l000cK87393418

Extracted artifacts 5

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0007_000.js` `dc37160715dd481d0bf49e7af5079aad16ed0e66896c1ae05ca27000b3e4454e`	pdf-javascript-stream	PDF /JS object 7 at offset 0x19B	259 bytes
`generic_stage_recovery_000.js` `1f9c41bac023af5173acb947acb1765aece4fb2d478d8f77dfc696cb5d6327ed`	deobfuscated-js	generic stage recovery split-literal-normalize from JavaScript object 7 at offset 0x19B	249 bytes
`annotation_subject_callee_hex_stage_000.js` `ed5a8aacbafda3eb8955288469a5767c5b8f37033338b90fd32f57c245a08b7f`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x14A	5198 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` `313aa79b032775cfa9ae69bd6eb15c77603e8a5ade2b55ee77f2ebfa1aa94b14`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x2D4	12249 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` `bc9cc1312e1ba23b0d964a592a0701ab9400b09bc08d9845e15603b679ec641b`	deobfuscated-js	PDF JavaScript deobfuscation pass	45480 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).

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