Malicious PDF — malware analysis report

Static analysis result for SHA-256 d27d9373be29a238…

MALICIOUS

PDF

8.5 KB
MD5: b73eb119597095a1ffd06c1b3391f420 SHA-1: 7277a4f27bcbcd4da4dfa7e8df69f5cf7a69993e SHA-256: d27d9373be29a238ae474460ecbc2e55a8cf2a7537fb0d7437cf5ac53b4ada1e
124 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

This PDF sample leverages CVE-2007-5659 by using the `collab.collectEmailInfo` JavaScript function to execute arbitrary code. The embedded JavaScript streams, particularly `numeric_charcode_stage_000.js`, are heavily obfuscated but indicate the execution of further malicious code. The ML classifier strongly flags this as malicious. The primary attack vector appears to be exploiting a known PDF vulnerability to achieve code execution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 6

  • 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)
  • 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. (identified after JavaScript deobfuscation)
  • 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.

FilenameKindSourceSize
javascript_obj0004_000.js
be4694a17eb89a55f7eb3db389ba2bc4f102f4c7dcfc99549d848cdb7df5dfb5
pdf-javascript-stream PDF /JS object 4 at offset 0xE1 1940 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
numeric_charcode_stage_000.js
6c41320119e160dc719997b9a2efb3600ea9d7e9d7e44b4dc2125762dc9f365f
deobfuscated-js numeric char-code string decoded JavaScript at offset 0xEF 505 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
5eb9f795b6810f377d84e0b669f896cbacc1e39b6d0df89b3d756cdc3dcbe9c9
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1C8D 1651 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
11b6f0f5701ca87462121ffd834c50818e085c9a4a0c339cc654678cdf5aab20
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x4C3 5112 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).