Malicious PDF — malware analysis report

Static analysis result for SHA-256 0511781201528a83…

MALICIOUS

PDF

12.5 KB
MD5: 51f3babfd9c59b715e51649387f23909 SHA-1: f519b75c2666f7b9a2268c8ea1cc5cafdbc9eadb SHA-256: 0511781201528a83070cf88e2ff76f7899ef4725badb5c0dad45a579dca6eb8c
310 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF sample contains embedded JavaScript that exploits CVE-2007-5659, specifically targeting Adobe Reader versions affected by APSB08-13. The script is designed to download a second-stage payload from the URL http://tabvaqretsbq.com/nte/KAND.asp/yH3d8a2aa9V03003f36002R0ee58237102T558682f2Q00000000901801F002d000aJ0c000501l0007. The deobfuscated JavaScript indicates a complex decoding mechanism for the payload. The presence of shellcode download URLs and exploit-specific heuristics strongly suggests malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • 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)
  • Adobe Reader APSB08-13 patch-range version gate (CVE-2007-5659) high CVE likely PDF_JS_ADOBE_APSB08_13_PATCH_GATE
    PDF JavaScript gates the exploit payload on (>= 8 && < 8.1.1) OR (< 7.1) — the Reader 7.0.x / 8.0–8.1.1 window patched by Adobe APSB08-13 for the CVE-2007-5659 Collab.collectEmailInfo buffer overflow. Only kits that target that exact bug check both of those patch points; benign scripts do not.
  • Annotation subject percent-decoding eval stager critical PDF_ANNOT_SUBJECT_MARKER_EVAL_STAGER
    OpenAction JavaScript forces annotation enumeration, reads an annotation /Subject payload with getAnnots(), rewrites marker bytes into percent escapes, decodes it with unescape(), and dispatches it through eval. This is a high-confidence exploit-kit staging pattern. It is intentionally not mapped to CVE-2009-1492 unless getAnnots() itself carries the crafted integer or long argument shape for that vulnerability.
  • ClamAV: Pdf.Exploit.Agent-36062 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36062
  • PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL
    Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
  • 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.
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://tabvaqretsbq.com/nte/KAND.asp/yH3d8a2aa9V03003f36002R0ee58237102T558682f2Q00000000901801F002d000aJ0c000501l0007

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
068944f8c011a88ab770b45c6de142b9305a1f515d410204d5eadd9ac2b5bfb3
pdf-javascript-stream PDF /JS object 7 at offset 0x19B 373 bytes
legacy_pdfkit_stage_000.js
10ffb2766188c3a4702c78f9e659d37fab8f394d7a716b2e834caee3c07e13e6
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2F5 12320 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
legacy_pdfkit_stage_001.js
edf2e2f6ef6a4e277c2ee27a4b94bbe82378af06c0afca43cf99cf027e38e596
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2F5 5121 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).