PDF malware analysis — malicious · e805809d6d145ef3

MALICIOUS

PDF

10.8 KB Authoring application: .a

MD5: 35b1aa4c35917ef4141ae75dbde646fa SHA-1: 58cfbce280c96771d6dc4c06c1912aa261a6fed6 SHA-256: e805809d6d145ef31efc519b4a3d3e5429f20146f4643fc915d79b99f42aaf5a

496 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.001 Malicious Link

This PDF file contains embedded JavaScript that is heavily obfuscated using arithmetic operations and percent-encoding. The script is designed to exploit multiple known Adobe Reader vulnerabilities, including CVE-2009-4324, CVE-2009-0927, CVE-2007-5659, and CVE-2008-2992. The primary goal appears to be the execution of a second-stage payload, as indicated by the 'arithmetic_percent_stage_000.js' artifact. The ML classifier also strongly flagged this PDF as malicious.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 12

media.newPlayer — CVE-2009-4324 critical CVE exact CVE_2009_4324

PDF JavaScript calls media.newPlayer — CVE-2009-4324 is a use-after-free in Adobe Reader's multimedia plugin triggered by media.newPlayer(). Actively exploited as a zero-day in December 2009. (identified after JavaScript deobfuscation)
Collab.getIcon — CVE-2009-0927 critical CVE exact CVE_2009_0927

PDF JavaScript calls Collab.getIcon — CVE-2009-0927 is a stack buffer overflow in Adobe Reader triggered by Collab.getIcon() with a crafted argument. Allows arbitrary code execution. (identified after JavaScript deobfuscation)
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)
util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992

PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure. (identified after JavaScript deobfuscation)
Multi-CVE Adobe Reader JavaScript exploit kit critical PDF_ADOBE_READER_MULTI_CVE_JS_KIT

One recovered JavaScript stage contains multiple version-gated Adobe Reader exploit branches. This is stronger evidence than independent API keywords: the PDF is selecting old Reader vulnerabilities by viewer version and running heap-sprayed Acrobat JavaScript exploit paths.
ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV

ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
Arithmetic percent-encoded JavaScript stager high PDF_ARITHMETIC_PERCENT_JS_STAGER

PDF JavaScript stores the hidden stage as many float*4 character code tokens separated by #, rebuilds a percent-encoded script with String.fromCharCode, then unescape/evals the recovered JavaScript. The decoder is gated on metadata-access launchers and requires recovered exploit-like Acrobat JavaScript.
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)
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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0018_000.js` `27c22e278f7a3eac135aa88605b6a6738823b998f760de6b5e45ea4346466aa6`	pdf-javascript-stream	PDF /JS object 18 at offset 0x4BA	162784 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`arithmetic_percent_stage_000.js` `1e390d5017129148e88418a8728db48739ebe6c1fec2f84cb550cf785545a969`	deobfuscated-js	arithmetic-percent decoded JavaScript object 18 at offset 0x4BA	7672 bytes
Detection ClamAV: Pdf.Exploit.Agent-35646 Obfuscation or payload: likely Carved artifact contains 12 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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