PDF malware analysis — malicious · 18dcd51d1e803ed6

MALICIOUS

PDF

8.0 KB

MD5: db4d0bcc77834e32c01be9f5892ae835 SHA-1: bff90e8df200aa3c04ac44dda63fea34a7dd92eb SHA-256: 18dcd51d1e803ed65a240be18b668bb7abec3eef832d2beeb9e1f10915e3df78

406 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains obfuscated JavaScript that exploits CVE-2007-5659, targeting specific versions of Adobe Reader. The script is designed to download and execute a second-stage payload from the URL http://berber2update.biz/cgi-bin/kln/z002106203r000cRab1694f9X56d54187Y7f1ead61Z0100f060. This behavior is consistent with a dropper or downloader malware.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 13

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.
ClamAV: Pdf.Dropper.Agent-7234224-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Dropper.Agent-7234224-0
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.
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.
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.
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.
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://berber2update.biz/cgi-bin/kln/z002106203r000cRab1694f9X56d54187Y7f1ead61Z0100f060

Extracted artifacts 5

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0005_000.js` `ab3f4be7a3e2e879e844dcace56ca59cf8fe7249dc5a05c90896f0c9e7dd732a`	pdf-javascript-stream	PDF /JS object 5 at offset 0x148	559 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`generic_stage_recovery_000.js` `a4b4429adacb2024b8caba42d9c825d5951c994d3abd76b46b9bae50590c28bc`	deobfuscated-js	generic stage recovery split-literal-normalize from JavaScript object 5 at offset 0x148	554 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_000.js` `d25f5bb963542cd6532069657f27f93af77fa9e15cba62e80d11fc40ee5dbcd5`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1A9B	1911 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` `b698ef186c72b5be67e3cc5ecd33c304580700e91e9eb555566f2af96b0b693a`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x374	4860 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`deobfuscated.js` `90117f1157c6796f7439840f5799e6024a78537b93c746748b18c62d2f03b78e`	deobfuscated-js	PDF JavaScript deobfuscation pass	23504 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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