PDF malware analysis — malicious · 01a65e2fc2c1e6e1

MALICIOUS

PDF

17.8 KB

MD5: 27c93e44d6c129f9cb7773a86bdc6bb3 SHA-1: 4811f05119ddefa0fa738cac9555eff830be863f SHA-256: 01a65e2fc2c1e6e1f84b7b43c7837f07e093ffdb7529e913dd0beffec6941207

366 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF contains heavily obfuscated JavaScript that exploits CVE-2007-5659 in Adobe Reader. The script is designed as a multi-stage dropper, reading encoded data from the annotation subject and using `String.fromCharCode` to reconstruct a payload. This payload then downloads a second-stage file from the embedded URL `http://cashspecialcar.com/news/data.html?...`. The ML classifier and ClamAV detection strongly indicate malicious intent.

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://cashspecialcar.com/news/data.html?ID=105664&fb=WVRveU9udHpPamc2SW5WelpYSmtZWFJoSWp0aE9qTTZlM002TWpvaWFXUWlPM002TnpvaU9EWXpNRE00T0NJN2N6b3hNam9pWVdSMlpYSjBhWE5sWDJsa0lqdHpPalk2SWpFd01qRXlOQ0k3Y3pvME9pSnJjSEJwSWp0T08zMXpPak02SW0xa05TSTdjem96TWpvaVpXVXdNV1k1TVRSbVlqQmpZMlZqTUdZMk1tWTVPVE0wTmpJME9HVmhZV0lpTzMwPQ%3D%3D/n002106201r0409R94e20927X6155e16fY08d5fd6eZ0100f070

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` `445613d7bf2cfb9c1156ea09f61076a8049f3c7e93fb809391b8cf86d1075920`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1E1D	14245 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` `f796f186bf3c509c4928cb7deb8c8e2fd236751d76e3d35040370ab28ec24841`	deobfuscated-js	nested inline base-23 callee-key decoded JavaScript at offset 0x1E1D	5796 bytes
`deobfuscated.js` `6ef272788629132315460b041e4401a76d957698a10dcd74e58e75fd6ce942e1`	deobfuscated-js	PDF JavaScript deobfuscation pass	142624 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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