PDF malware analysis — malicious · 8dcd691e71447599

MALICIOUS

PDF

15.0 KB

MD5: b3b5374155e4154a5d22ff1823aba1e8 SHA-1: 5d378493b5e6a9849af4569cfd2b3365c944fa1d SHA-256: 8dcd691e71447599132978f8c281cef2cefd1576d64c49f91e073ed63b7a26bb

194 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript/JScript T1204.002 Malicious Link/URL

This PDF file contains heavily obfuscated JavaScript, as indicated by multiple heuristic firings including 'PDF_JS_OBFUSCATED_DROPPER' and 'CVE_2007_5659'. The embedded JavaScript is designed to be a multi-stage dropper, exploiting the CVE-2007-5659 vulnerability. The deobfuscation process revealed complex encoding and execution methods, typical of exploit delivery. The primary attack vector is the exploitation of the Collab.collectEmailInfo method, leading to the execution of further malicious code.

Heuristics 8

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)
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.
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.

Extracted artifacts 3

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` `7abe69a3ac35e7572f7334e80860e77049bc45d880534ad608cfd94d11677f93`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x194A	12062 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` `2e8495ee242dad45e82b8ed060e455c4c79892a9e810be4a75a22d06abf75bb1`	deobfuscated-js	PDF JavaScript deobfuscation pass	114234 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 9 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).

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