Malicious PDF — malware analysis report

Static analysis result for SHA-256 80dcc8aef96d4558…

MALICIOUS

PDF

15.1 KB
MD5: a53d8df53399e6ed8a5ded6567991c25 SHA-1: ba1186b0385995be8ccf884a28c2283e032eb3f0 SHA-256: 80dcc8aef96d45581866a9c02dafffc8a59950b04db3c3531721aa033d812d9d
194 Risk Score

Malware Insights

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

The PDF file contains obfuscated JavaScript that leverages the CVE-2007-5659 vulnerability (Collab.collectEmailInfo). The JavaScript is designed as a multi-stage dropper, indicated by the 'PDF_JS_OBFUSCATED_DROPPER' heuristic. It appears to deobfuscate and execute further stages, ultimately leading to the download and execution of a malicious payload. The ClamAV detection 'Pdf.Exploit.Agent-35901' further confirms its malicious nature.

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.

FilenameKindSourceSize
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
73024a96f972237cd89a9ab0e7a77b8fad6a57fd8651365b27a7a2cf53ff68aa
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1965 12029 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
959f90ef4667e151155e204c5dbf63b8b5ab7fade37b3723d3f05f7e08e4ee30
deobfuscated-js PDF JavaScript deobfuscation pass 120832 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).