PDF malware analysis — malicious · 6c7f3ba98377f82b

MALICIOUS

PDF

18.1 KB

MD5: 8e8021439ca015728f6f5bfd555f712f SHA-1: e580d8af7cffb4a24285de7274a2226fef907326 SHA-256: 6c7f3ba98377f82b62ed66d2a9f745e8f585f02577bb3607c210dfa2689cd922

366 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF contains heavily obfuscated JavaScript that exploits CVE-2007-5659, targeting specific versions of Adobe Reader. The script is designed to read encoded data from an annotation subject, decode it, and then execute it. This decoded payload is responsible for downloading a second-stage file from the embedded URL 'http://yourrosemont.com/news/data.html?ID=105192&fb=WVRveU9udHpPamc2SW5WelpYSmtZWFJoSWp0aE9qTTZlM002TWpvaWFXUWlPM002TnpvaU5UTXdNVEk1T1NJN2N6b3hNam9pWVdSMlpYSjBhWE5sWDJsa0lqdHpPalk2SWpFd01qRXlOQ0k3Y3pvME9pSnJjSEJwSWp0T08zMXpPak02SW0xa05TSTdjem96TWpvaU5UWXlOV0kxTW1VeE9EZ3pObVE1Tm1FME5tWmxZelZpWlRrMVlqTmpaRFVpTzMwPQ%3D%3D/n002106201r0809R6fb42e12X09185be9Y780f69abZ0100f080'. The presence of exploit code and a download URL strongly indicates a malicious dropper.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 12

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 static 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.Exploit.Agent-35901 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-35901
Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER

PDF JavaScript shows 5 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, hex_dashed_payload, incremental_eval_build, 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://yourrosemont.com/news/data.html?ID=105192&fb=WVRveU9udHpPamc2SW5WelpYSmtZWFJoSWp0aE9qTTZlM002TWpvaWFXUWlPM002TnpvaU5UTXdNVEk1T1NJN2N6b3hNam9pWVdSMlpYSjBhWE5sWDJsa0lqdHpPalk2SWpFd01qRXlOQ0k3Y3pvME9pSnJjSEJwSWp0T08zMXpPak02SW0xa05TSTdjem96TWpvaU5UWXlOV0kxTW1VeE9EZ3pObVE1Tm1FME5tWmxZelZpWlRrMVlqTmpaRFVpTzMwPQ%3D%3D/n002106201r0809R6fb42e12X09185be9Y780f69abZ0100f080

Extracted artifacts 4

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0005_000.js` `4718a27c2224fc36bf24f8e8e04598f1ad78adce4401c7be2708318738a6983d`	pdf-javascript-stream	PDF /JS object 5 at offset 0x148	469 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_000.js` `f6aedca824e1cf521f22611bd4b9908e4017df43cae9bb180802b0856ca27168`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1EBD	14515 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).
`legacy_pdfkit_stage_001.js` `f067e836fd376f98b87625cfa374fbfe20757821f3e797f33d71072c44eb2932`	deobfuscated-js	nested inline base-23 callee-key decoded JavaScript at offset 0x1EBD	5959 bytes
`deobfuscated.js` `d014f17523d4f48c4eee1d763748dfcedeb181372106a7b7249ee5a29e9c0f0e`	deobfuscated-js	PDF JavaScript deobfuscation pass	89384 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 10 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).

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