PDF malware analysis — malicious · a4b6d847de9e43b8

MALICIOUS

PDF

7.8 KB

MD5: 86cbb346bfd16d49c1a6afc0976dd7bb SHA-1: 90ee2d572f07b3d092efc8b902c091b39885362e SHA-256: a4b6d847de9e43b87db175fd59a960bf021dc0d05a3e35e58d315f506a335925

194 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

The PDF contains obfuscated JavaScript, identified as a dropper, which leverages the CVE-2007-5659 vulnerability. This vulnerability is exploited through the `Collab.collectEmailInfo` method to execute the embedded JavaScript. The script is designed to download and execute a second-stage payload, as indicated by the 'Obfuscated multi-stage PDF JavaScript dropper' heuristic.

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 JavaScript deobfuscation)
ClamAV: Pdf.Dropper.Agent-7289572-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Dropper.Agent-7289572-0
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.
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 4

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0005_000.js` `9d5c7e01faed5b04e9ec11f1d98b73f0012c871beaf60e9f9d32ad6df00d46f7`	pdf-javascript-stream	PDF /JS object 5 at offset 0x148	550 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` `d0c8bf52d7571a05120d2e1cc87262638ec7aea9e0262565b608c69513a2d7b2`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1A31	1708 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` `2886c5a9d9df41993d2a51164ca25e489d1e34dbc46cffd35df56db8c21ac050`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x359	4927 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`deobfuscated.js` `9a7962825099d1403a2c86b550c0c8e218f6f859bbd7104c2d074853fa194b43`	deobfuscated-js	PDF JavaScript deobfuscation pass	21070 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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